Multilayer radiation sensitive element having controlled triboelectric charging characteristics

ABSTRACT

Methods for adjusting the charging characteristics of surfaces are disclosed. A preferred embodiment relates to methods for altering the contact surfaces of materials that are ordinarily subject to the production of relatively large scale triboelectric effects when such a surface is frictionally contacted with another surface, to thereby eliminate or minimize the potential for undesired static electric discharge, for example. The present methods involve altering such a surface with a &#39;&#39;&#39;&#39;charge control agent&#39;&#39;&#39;&#39; as defined herein to thereby provide a desired, predetermined adjustment in the triboelectric charging propensity of the surface. Specific products having minimized, maximized, narrowly adjusted (as desired) surface impact charging characteristics are disclosed.

Bailey, Jr. et a1.

[ MULTILAYER RADIATION SENSITIVE ELEMENT HAVING CONTROLLED TRIBOELECTRICCHARGING CHARACTERISTICS [75] Inventors: William J. Bailey, Jr.; JamesF.

Houle; Gilden R. Van Norman, all of Rochester, N.Y.

[73] Assignee: Eastman Kodak Company,

Rochester, N.Y.

[22] Filed: Jan. 21, 1974 [2]] Appl. No.: 435,359

Related U.S. Application Data [63] Continuation of Ser. No. 163,450,July 16, 1971,

abandoned.

[52] U.S. Cl 96/87 A, 96/68, 96/1 14.2

[51] Int. Cl G03c 1/78 [58] Field of Search 96/87 A, 87 R, 68, 85,

1 56] References Cited UNlTED STATES PATENTS 3.253.922 5/1966 Chu et a1.96/85 3.532501 10/1970 Mackey et a1. 96/87 3,547.643 12/1970 Pechmunn96/87 3.549.369 12/1970 Koda et a1. 6/87 Nov. 26, 1974 3,549,375 12/1970Pechmann 96/87 3,551,152 12/1970 Mackey et a1. 3,552,972 1/1971 Meyer eta1 3,573,093 3/1971 Oshibuchi ct a1 96/87 3,589,906 6/1971 McDowell eta1. 913/] 14.5

3,607,286 9/1971 Wood 96/87 3.666.478 5/1972 Groh et a1 96/94 PrimaryExaminer-Ronald H. Smith Assistant Examiner-Edward C. Kimlin Attorney,Agent, or Firm-E. W. Milan [57] ABSTRACT Methods for adjusting thecharging characteristics of surfaces are disclosed. A preferredembodiment relates to methods for altering the contact surfaces ofmaterials that are ordinarily subject to the production of relativelylarge scale triboelectric effects when such a surface is frictionallycontacted with another surface, to thereby eliminate or minimize thepotential for undesired static electric discharge, for example. Thepresent methods involve altering such a surface with a charge controlagent as defined herein to thereby provide a desired, predeterminedadjustment in the triboelectric charging propensity of the surface.Specific products having minimized, maximized, narrowly adjusted (asdesired) surface impact charging characteristics are disclosed.

49 Claims, No Drawings MULTILAYER RADIATION SENSITIVE ELEMENT HAVINGCONTROLLED TRIBOELECTRIC CHARGING CHARACTERISTICS This is acontinuation, of application Ser. No. 163,450 filed July 16, 1971, nowabandoned.

The present invention relates to the general subject of staticelectricity formation and accumulation or discharge when one surface isfrictionally contacted with another. More particularly, this inventionrelates to novel processes and compositions useful in influencing, in adesired manner, the impact charging characteristics of such surfaces.

THE PROBLEM In the manufacture and use of polymeric film products andespecially sensitized (radiographic or photographic) materials, thegeneration of static electrical charge is a serious problem. In the caseof sensitized goods the most serious deleterious effects are producedwhen accumulated electrical charges discharge, producing light and/ornoise, which is recorded as an image on photosensitive materials and asstatic on other materials such as magnetic tape that are sensitized toother specific, non-visible electromagnetic irradiations. Such dischargemay occur in the course of manufacturing processes, such as coating,finishing or packaging, or it may occur during use of the finishedproduct in cameras, printers, tape players and other associatedequipment.

Another less obvious deleterious effect which results from accumulationof charge on polymeric supports, coated or uncoated, in themanufacturing operation, is the production of coating defects such ascore mottle" and roll convolution repeat, both of which are well knownto those involved in the manufacture of these types of materials. Bothof these undesirable effects are due to the uncontrolled, undesirablebuild-up of localized electrically charged areas on, or in the variousproducts in the course of the film manufacturing operation.

These areas of localized charge give rise to nonuniformity in theoverlying sensitized coatings during their application and consequentlythe aforementioned manifestations of this non-uniformity.

Although there are a large number of manipulative ways in which suchundesirable (and often hazardous) static electrical charges can begenerated, the term most applicable to the generation of electricalcharge in the manufacture and use of sensitized goods istriboelectricity. This term refers generally to the electrical chargegenerated by the contact or dissociation (physical separation) of twosurfaces. Usually, but not always, the two surfaces are dissimilar. Theamount of charge generated in this fashion is dependent upon severalfactors, the most important being: l the intimacy of contact; (2) thetime of contact; and (3) the nature of the surfaces brought intocontact. It is significant, however, that multiple contacting anddissociation of different surfaces during the various manufacturingoperations can, and very often do, result in the build-up" of very largecharges of so-called static electricity" in and on the various productsand parts of equipment involved in such operations; the net effect uponthe charge induced upon the contacted surface(s) being known as thetriboelectric effect" of such contact and dissociation. Apparently eachcontact between surfaces results in a specific charge effect upon thesurfaces involved, generally with a total cumulative charge being builtup on the surface(s) in an additive manner; the particular electricallyconductive nature of the material in question is generally determinativeof the actual observed rate of build-up. Unfortunately, very fewpolymeric films or coated photographic film materials are sufficientlyelectrically conductive by themselves to prevent static electricitybuild-up to an objectionable degree during the ordinary processing ofsuch materials.

There have been many approaches to eliminating'or minimizing so-calledstatic-defects" which are the manifestation of the presence of excessivetriboelectricity. Inasmuch as a static mark in photographic products isthe result of light recorded by the sensitized layer, there is a certainminimum electrical charge required before a discharge which produceslight of sufficient intensity or duration to be recorded by a particularsensitized layer can occur. In the case of a polymeric film such ascellulose acetate coated with a conventional, mainly gelatin-basedphotographic emulsion, for example, static discharge occurs when a nettriboelectric charge of +810 esu (electrostatic units per squarecentimeter) at a given part of the emulsion is reached. This figure willof course vary quite broadly with materials, humidity conditions, etc.In this instance, the mainly gelatin surface of the emulsion exhibits amarked positive triboelectric tendency, measured against many surfaceswith which such a mainly gelatin layer is contacted during itsmanufacture. Other surfaces accumulate negative triboelectric chargespreferentially. However, undesired static discharge can occur due toeither excessively negative or excessively positive surfaces. Anydiscussion of proposed solutions to the static defects problems shouldbe with an understanding of the foregoing factors which govern the typeand relative amount of charge generated between generally dissimilarsurfaces.

PRlOR ART There have been, and continue to be, an almost endless list ofattempts to prescribe methods for decreasing or eliminating theeffect ofcharge accumulation. The intimacy of contact of the surfaces ofphotographic materials has been altered by incorporating matting agentsinto one or more of these surfaces. These modifications have been onlypartially effective since the duration and/or multiplicty of contactsoften destroys any benefit achieved by reducing intimacy of contact.Time of contact can be varied, but not within sufficiently practicallimits to alleviate the problem and furthermore, this type of approachgenerally involves modification of "external influences" which occur inthe environment of the film.

Perhaps the best known and most widely used type of effort to solve thisproblem involves the incorporation of so-called conductive materials orlayers as a film backing or in mixture with a binder to hopefullyconduct the electrical charge to ground as it occurs to avoid anydischarge sufficient to produce recordable static" energy. Some of theconductivity improving" materials, although highly conductive, arethemselves quite prone to generating large quantities of electricalcharge when contacted with a dissimilar material. Thus, so much chargeis often generated in each single impact that the charge cannot beconducted to ground rapidly enough to prevent static discharge fromoccurring. Furthermore, the great bulk of such conductivity improvingmaterials depend upon an environment having a relatively high relativehumidity to perform well as conductors of static electricity. Forexample, whereas they may perform satisfactorily as conductors underconditions of relative humidities of 50 percent or more, many of themcannot conduct adequately when they are made or used in atmosphereshaving relatively low humidities, on the order of percent or even less.This type of experience results from the use of ionic and/or hygroscopicmaterials which depend for their conductive properties upon theirability to dissociate under high humidity conditions. Often surfacetackiness is another problem associated with the use of suchconductivity improving materials that function in this manner. Anoutstanding example of the tackiness phenomenon occurs in the case wherean ionic or hygroscopic conductivity agent is incorporated into the gellayer of, for example, a poly(ethylene terephthalate) or other polymericbased photographic element in an attempt to prevent static dischargewhich ordinarily occurs during the emulsion coating operation due tocontact of the sub with rollers, etc. In order for this type ofconductivity agent to perform satisfactorily, humidity levels within thecoating machine must be maintained at about 50 percent. At this level,however, the gel sub becomes tacky and results in what is popularlycalled gel-pickoff" in the film coating art. In this case the tackinessof the gel layer causes small pieces of gel to adhere to thetransporting and other rollers giving rise to a sub layer replete withholes and in turn a very poor emulsion overcoat. The picked-off gel maybecome redeposited from the rollers back onto other areas of the filmproducing gel spots, another undesirable defect. Clearly, in manyinstances, it is desirable to minimize or eliminate static discharge bysome method other than the use of such hygroscopic conductivjtyimproving" materials.

Since the contacting and dissociation of dissimilar surfaces during themanufacture of various photographic and radiographic elements is quitenecessary, it appears from the prior art and prior to the presentinvention that the problem of excessive charge generation due totriboelectric effects (along with the concomitant relatively largeamount of waste or unsatisfactory product) had to be accepted as a partof the cost of being in this business, since this phenomenon is anatural physical occurrence. All prior attempts at solving the problemof static discharge" have apparently been directed to trying to drainoff the charge quickly and efficiently, rather than attempting toovercome this apparent natural physical occurrence" in the firstinstance.

OBJECTS lt is therefore an object of the present invention to provide amethod for controlling, within prescribed useful limits, the chargingcharacteristics of materials utilized in the manufacture of radiationand/or photosensitive materials.

lt is another object of the present invention to provide photosensitiveproducts whose outermost surfaces are either (a) substantially chargefree when impacted with dissimilar materials or (b) alternatively,produce sufficiently low levels of charge when so impacted that chargeaccumulation in their normal environment is not sufficiently high as toproduce discharge; or if charge accumulation does occur under severeenvironmental conditions, means are provided to conduct this charge offof the surface in a controlled fashion without discharge or any of theaforementioned problems.

It is yet another object of the present invention to provide a methodfor establishing the triboelectric charging characteristics of surfacesintended for almost any use at any predetermined level based upon thenature of the treated surface and that with which it is brought intocontact. Thus, these characteristics may be minimized or carefullycontrolled within relatively narrow limits.

Other objects and advantages of the present invention will be madeobvious to those skilled in the art by consideration of the followingdescription.

SUMMARY OF THE INVENTION According to the present invention, there isprovided a method for doctoring the surfaces of materials normallysubject to the generation of a triboelectric charge when a surfacethereof is brought into contact with another usually dissimilar surfaceby modifying the surface of the material with a sufficient amount of aselected charge control agent to thereby provide to that surface apreselected, desired triboelectric charging characteristic.

According to a preferred embodiment, selection of the charge controlagent" and adjustment of charging characteristics comprise the steps of:

a. measuring the electrical charge generated when the surface of thematerial normally subject to triboelectric charging is brought intocontact with another selected, usually dissimilar surface undercontrolled conditions;

b. measuring the electrical charge generated when surfaces containingcharge control agents are brought into contact with a similar usuallydissimilar material under controlled conditions;

c. based on the results of step (b) selecting a charge control agent"which provides the adjustment desired for controlling the chargingcharacteristics of the material; and

d. modifying the surface of the material with a sufficient amount of thecharge control agent" selected in step (c) to produce the desiredadjustment in the charging characteristics of the surface of thematerial.

There are also provided herein a number of specific radiation sensitivematerials and film base materials in which surface chargingcharacteristics have been substantially nullified utilizing theforegoing technique; said materials comprising elements having chargecontrol agents, (as defined in detail hereinafter) incorporated into oneor more layers thereof.

More specifically, charge control agents" of the following genericclasses have been found to be suitable additives in certain limitedclasses of materials:

A. surfactant materials having the generic structure:

wherein:

A is a member selected from the group consisting of hydrocarbon chainspartially fluorine substituted hydrocarbon chains and fluorocarbonchains;

Z is a member selected from the group consisting of n is an integerranging from l to about 8; D is wherein R,, R and R are selected fromthe group consisting of hydrogen, lower alkyl and aryl; and X is ananion. According to the preferred embodiments of the present invention Xis selected from the group consisting of chloride, bromide, iodide,nitrate and phosphate ions;

B. compounds of the following structural formula:

wherein:

Z represents the atom necessary to constitute a member selected from thegroup consisting of aromatic hydrocarbon rings and alicyclic structures;

R is selected from the group consisting of single and multiplesubstitutions of members selected from the group consisting of halogen,nitro, nitroso, hydroxyl, carboxy, cyano, alkoxy, aryloxy, substitutedalkoxy and wherein R, is alkyl, aryl, substituted alkyl, or substitutedaryl;

X is a member selected from the group consisting 0 o I 0 11 1t 0 I ll llI II and CH=CH- wherein n is an integer from 1 to about 10;

Y is a member selected from the group consisting of HOOC-R-COOH whereinR is selected from the group consisting of:

LII

6 (2) (CH) (Cl/R1) I \R'Z n (a) 0th).. 0 (CH2)m where if R=(l) or (2)and R, is hydrogen, R is selected from the group consisting of halogen,nitro, aryl, substituted aryl, hydroxyl,

where if R--(3) R, and R may be hydrogen, halogen, nitro, carboxyl,aryl, substituted aryl, alkyl, and substituted alkyl n and m areintegers which may be the same or different, and where R, is H, R may behydroxyl D. carboxylated polymers in the free carboxyl form as describedhereinafter;

E. compounds of the formula wherein 1. R, is CH (CH and n is an integerranging from about I to about 19, then R may be H, R,, or R, with adifferent value for n 2. R, and/or R may be unsaturated hydrocarbonresidues 3. R, and/or R may be aryl or substituted aryl 4. R, mayrepresent atoms of a polymeric structure in which case R may be H or asotherwise defined above; and M may be H, NH, or an alkali metal cation;and F. polymeric structures having a repetitive substituent capable ofcontributing a negative charging influence, as defined in greater detailhereinafter.

DETAILED DESCRIPTION OF THE lNVENTlON At this stage of the discussion,it would perhaps be helpful to define internal environment" and externalenvironment as it relates to the static generation problem, as thisterminology will be used frequently hereinafter. By internal environmentis meant the manufacturing or in process environment which a particularproduct encounters in the course of its manufacture. Thus, chargesgenerated on roll and emulsion coating machines, slitters, packagingapparatus, etc., are a result of internal" environment and will bereferred to as internal charging.

The term external environment" defines all of those materials, surfaces,etc., which the finished products 5 experience after completion of themanufacturing and problems experienced in this external environment willbe referred to as external charging problems.

As one might expect, internal charging problems can often be correctedor eliminated by modification of manufacturing equipment to match thesurfaces thereof to the surface of the processed material so thatcharging effects are reduced to a minimum. Such alterations are,however, often quite difficult and expensive, and, as a practicalmatter, all but impossible without extensive and costly re-engineeringetc. In the case of external problems, however, such modification is allbut impossible since the film manufacturer has no control over types ofparts in, or the design of, the particular equipment in which themanufactured material is to be used, or any other aspect of the productsexternal surroundings.

The term charge control agent as utilized herein and in the claimsappended hereto refers to a material of known triboelectric chargingpropensity as determined in the apparatus and according to the methoddescribed in US. Pat. No. 3,501,653 to W. J. Bailey, Jr. issued Mar. 17,1970, or some equally accurate technique, which material is also capableof incorporation into or coating on a surface to adjust thetriboelectric charging characteristics thereof. Specifically preferredmaterials within this broad class are described in detail below and arecapable, when properly selected, of minimizing the generation of staticelectrical charges in many products including, for example, radiationsensitive film and polymeric materials of the type used in film,sheeting fabric and carpet manufacture. As described hereinafter,maximization or intermediate adjustment of surface chargingcharacteristics may also be achieved using the techniques describedherein.

The foregoing charge control agents are further distinguished fromconductivity agents i.e., materials which due to the fact that they arehygroscopic and/or ionic tend to conduct or bleed off static chargesgenerated by contact between two surfaces thereby minimizing theaccumulation of same. Thus, in the preferred embodiments disclosedherein, charge control agents" can be used to minimize, maximize oradjust to a prescribed level the propensity of a given surface togenerate static electrical charges when contacted with another usuallydissimilar surface, while the conductivity agents of the prior artmerely minimized the accumulation of static electrical charges ex postfacto, i.e., after generation thereof.

The instant pursuit of a solution to the abovedescribed problem wasinitiated by subjecting the phe nomenon itself to systematic scrutiny,as opposed to pursuing attempts to compensate for the phenomenon onceits effects manifested themselves as had been done with conductivityagents, for example, in the past. Thus, a method for accuratelymeasuring the magnitude of the effects had to be devised to determinethe mechanism, effects and charging propensities of various materials.Several methods were available to evaluate or measure the amount ofaccumulated charge built up when dissimilar materials were brought intocontact or removed from contact. Such prior art methods involvedmeasurement of contact potential between dissimilar materials; blockingpotential; charge accumulation due to rolling or sliding friction; etc.

Most of these methods involved so many variable factors in the systemunder study that in many cases anomalous results or results which werenot a true measure of the net charging propensities of the surfacesinvolved were obtained. A method of measurement which eliminates many ofthe variable factors in some of the earlier equipment and yields resultsmore clearly dependent upon actual surfaces, time of contact andpressure is identified as the impact electrification method. Aninstrument to measure impact electrification is described in US Pat. No.3,501,653 to W. J. Bailey, Jr. issued Mar. 17, 1970. The instrument andthe measured values obtained in the use thereof are defined andexplained thoroughly therein and the disclosure of this patent isincorporated herein by reference. Stated simply, the theory of Baileysapparatus is that if accurate comparative values for impactelectrification of a variety of surfaces is to be determined, a givenreference surface must be impacted by a second (reference) surface andseparated, all in a controlled and repeatable manner. The electricalcharge generated by the impact and separation is accurately measured andrecorded. The values obtained are most conveniently expressed inelectrostatic units per square centimeter (esu/cm). The amount ofelectrical charge in esu/cm responsible for discharges causing staticmarking for some photographic elements is discussed hereinafter.

With such an instrument one is able to study the effects on theelectrical charging behavior of various surfaces. Furthermore, one isable to relate these data to behavior of such a surface when used inconjunction with a photographic element provided that certain variablesare brought into consideration.

With this impact electrification measuring apparatus and technique, adetailed study was initiated to determine the relationship betweenchemical structure and electrical charging behavior; namely impactelectrification. It was postulated that if such a relationship could bedetermined, one could possibly use the same to design compounds ormaterials which control the electrical charging behavior of photographicelements such that a static discharging amount of potential would not beobtained in the first instance. it was then discovered that thisdesirable goal can be accomplished by practicing the present invention.Furthermore, it was found that the control of surface charge to aidcoating uniformity of the sensitized portions of the element (ratherthan detract from it) is also possible, and can be. accomplished bypracticing the instant invention. Thus, according to the presentinvention there is provided a method for adjusting the chargingcharacteristics of materials normally subject to the generation of anelectrical charge when a surface thereof is brought into contact withand dissociated from another (usually dissimilar) surface by modifyingthe surface of the material with a sufficient amount of a selectedcharge control agent to provide a desired preselected chargingpropensity. According to a preferred embodiment of the inventiontesting, selecting and adjusting technique comprises the steps of:

a. measuring the electrical charge generated when the surface ofmaterial normally subject to triboelectric charging is brought intocontact with another usually dissimilar surface under controlledconditions;

b. measuring the electrical charge generated when surfaces of chargecontrol agents" are brought into contact with a similar usuallydissimilar material under controlled conditions;

c. based on the results of step (b) selecting a charge control agentwhich provides the adjustment desired for controlling the chargingcharacteristics of the material surface; and

d. modifying the surface of the material with a sufficient amount of thecharge control agent selected in step (c) to produce the material.

According to the method of the present invention, a surface which issubject to charging upon physical contact with another dissimilarsurface is tested, preferably in the apparatus described in theaforementioned U.S. Pat. No. 3,501,653, to determine the electricalcharge generated when the surface is brought into contact with aspecific dissimilar material under carefully controlled and reproducibleconditions of time, impact force, intimacy of contact, relativehumidity, etc. to determine the charge generated under such conditionsof controlled impact and dissociation. Once a value has been determinedfor this charge, a variety of other surfaces of charge control agentsi.e., materials which may be incorporated onto or into the surfaceoriginally evaluated, as defined hereinabove, are similarly tested byimpacting under the same controlled conditions with the same generallydissimilar surface. From the results obtained in the two evaluationsjust described a charge control agent which demonstrates chargingcharacteristics, which, when added to those of the surface to bealtered, provide the desired surface charging adjustment is selected andan amount sufficient to provide the desired alteration coated on orincorporated into the surface. According to a preferred embodimentwherein it is sought to minimize the propensity of the surfaces ofradiation sensitive film base or radiation sensitive elements togenerate static electrical charges when contacted with specificreference surfaces charge control agents demonstrating triboelectriccharging propensities of about the same magnitude, but of oppositepolarity as the surface whose charging is sought to be controlled areselected and amounts thereof sufficient to neutralize or nullify thecharging of the surface incorporated therein, in, for example, thesurface formation operation i.e., casting, extrusion, etc., or bycoating of a very thin, continuous or discontinuous, layer of the chargecontrol agent over the surface whose charging characteristics are beingaltered. A brief single demonstrative example of which many more will bepresented hereinafter exists in the case of sensitized photographicmaterials as already mentioned above.

ln the manufacture of silver halide sensitized photographic materialsthe light sensitive silver halide is suspended in a gelatin emulsionwhich is in turn coated, generally at a very high speed, on a celluloseester, poly(ethylene terephthalate) or other suitable support. In thecase of poly(ethylene terephthalate) materials, due to the hydrophobicproperties thereof, it is necessary to pre-coat" the support with anemulsion adherence improving gelatin sub of the type well known to thoseskilled in the film manufacturing art. This sub" is applied directly tothe polymeric support or a u-coat applied thereunder and dried. Thecoated support is then emulsion coated at high speed in a rollertransport coating machine or other suitable transport mechanism whichmight similarly produce triboelectric charging. With each impact of thegel subbed surface with a stainless steel or anodized aluminum rollerduring the emulsion coating operation a charge is produced whichultimately may result in a discharge if the accumulated static achievesor exceeds a prescribed discharge threshhold level. To control thisphenomenon in accordance with the technique described herein, a surfaceof the gel sub was tested to determine its impact electrificationpotential in the apparatus and according to the method described in theaforementioned US. Pat. No. 3,501 ,653. The results of this testindiciated that at an impact pressure of 20 psi, relative humidity of 5percent, F and other controlled conditions specified below, the gelsurface produced a charge of about +20 esu/cm when the impactingmaterial, i.e., the roll material was stainless steel. Testing undersimilar environmental conditions utilizing surfaces of a variety ofcharge control agents, i.e., materials capable of incorporation into thegel surfaces, which demonstrate their own individual chargingcharacteristics, indicated that a class of materials identified as groupA or B, described in detail below, had very strongly negative chargingcharacteristics on the order of 30 esu/cm With this information in hand,small amounts of these negative charging agents were incorporated intothe gel sub and with some small amount of varying of ratios it wasdiscovered that if concentrations of from about 1 g/g of gel to about 2g/g of gel of these materials were used, a surface which demonstrated acharge of about 010.5 when tested according to the technique of US. Pat.No. 3,501,653 could be produced.

Further efforts in this area indicated that it was possible byincorporating relatively small amounts, on the order of 0.005 percent byweight of the fluorocarbon materials of group A above, into the gel subto produce subbed support materials which generated almost no chargewhen impacted in the controlled fashion described. These materials whensubsequently emulsion coated in a conventional apparatus utilizingstainless steel rolls demonstrated uncommonly low levels of staticcharging over a broad range of humidity conditions, thus providingexceptional processing advantages, and emulsion coated product which wasfree of static marking.

Although in the preferred embodiment, the charge magnitude of the chargecontrol agent approximates that of the surface whose charge is beingdoctored, (except, of course, that it is of the opposite polarity) itshould be obvious that in fact such close matching of charge magnitudeis not absolutely necessary since a relatively smaller amount of acharge control agent which demonstrates a charging propensity of greatermagnitude can be incorporated into or coated on a charging surface toachieve a combined charging potential of about zero. Such a combinationof high magnitude charging charge control agent and a charging surfaceof opposite polarity and relatively lower charging potential providesthe added advantage that only very small quantities of the control agentneed be introduced into the very sensitive and delicately balancedphotographic systems in which the product is primarily useful, therebyreducing the possibility of sensitiomet ric problems which may and oftendo arise when additives are incorporated into such materials.

It should also be noted that although a wide variety of charge controlagents" including ionizable salts, acids, alcohols, esters, ethers,etc., as described in detail hereinafter, may be incorporated to providethe desired charge control, it is particularly advantageous if thecharge control agent is a surfactant since this permits the formation ofa hybrid" surface of charge control agent and charging surface withrelatively minimal concentrations of the former, thereby furtherreducing the amounts of charge control agent which must be added toachieve the desired level of charge control and concurrently the levelof potential problems which may result from such incorporation by theuse of surfactants; however, care should be taken not to combineinteracting or reacting surfactants or charge control agents as will bedescribed in greater detail below. Use of such interacting materials canoften result in undesirable repellency characteristics and/or evensensitiometric defects and reasonable care must be exercised to avoidany such use.

The foregoing discussion has been directed primarily to the control ofcharging so as to provide a surface which, when subjected to impactcharging, produces a charge of about esu, as is desirable in themanufacture of photosensitive products. The techniques described can besimilarly employed to enhance or increase the magnitude of the chargeproduced on a surface upon impact. For example, in the application oftoners to exposed areas in electrophotography, it is necessary toproduce a very high charge on the surface of the toner particles toinsure their repulsion by the non-image, similarly charged areas andattraction to the oppositely charged image areas. Hence, in thisapplication, the desire is indeed to increase the surface charging ofthe toner particles or the imaging materials to some predeterminedrelatively high level and this can be accomplished by the incorporationof a suitable high charging charge control agent into or onto thesurface of the tonerparticles to substantially increase the surfacecharge of the toner to any desired level and any desired polarity. Theselection of surfactant materials or alternatively materials which canbe coated in very thin layers or imbibed into the surface for this purpose produces advantages similar to those stated for photographic usagesin that lesser concentrations of such materials are required to producesurfaces havin relatively large concentrations thereof.

Thus, as should be clear the method of charge adjustment or surfacealteration described herein is equally applicable to increasing theimpact charging characteristics of surfaces as to reducing the same tothe zero level, as is highly desirable in the case of the manufacture ofradiation sensitive materials.

As a further alternative, due to the differences which occur betweeninternal and external static inducing environments it may be necessaryto include on the surface of a given product in addition to one or moreof the charge control agents" described above, a more conventionalconductivity" agent which would'serve to conduct or bleed offtriboelectricity produced over and above certain maximum thresholdlevels as defined for specific products.

This phenomenon can once again be defined in terms of the photosensitivematerial described above wherein the technique of the instant inventionis utilized to select a charge control agent" or combination of chargecontrol agents which are incorporated into the gel sub surface toeliminate static effects in the internal environment, due to impact witha specific impacting material, namely stainless steel rollers. This sameproduct may, however, after sale, be subjected to an externalenvironment including impacts with plastic, rubber, aluminum, etc.,materials for which the original charge control agent provides little ifany protection,

and may indeed actually tend to produce increased charging.

Under these circumstances, the incorporation of a conductivity agent aswell as a charge control agent becomes a requirement to insure that thearticle is free of the effects of charge accumulation. Such combinationswill be discussed further and examples thereof presented hereinbelow.

As alluded to hereinabove, the use of mixtures or combinations of two ormore charge control agents to achieve very exact definitions of thesurface charging characteristics of a given material may also beadvantageous, and combinations of this type will be demonstrated in theexamples below.

Some specific examples of photosensitive products developed as a resultof utilization of the above described technique and utilizing materialsevaluated in the foregoing examples will now be defined in detail.

Among the types of materials which have been found useful as chargecontrol agents to date are the following classes of compounds:

A. surfactant materials having the generic structure:

wherein:

A is a member selected from the group consisting of hydrocarbon chains,and partially and per-fluorinated hydrocarbon chains;

Z is a member selected from the group consisting of n is an integerranging from to about 8 D is wherein:

Z represents the atoms necessary to constitute a member selected fromthe group consisting of aromatic hydrocarbon rings and alicyclicstructures;

R is selected from the group consisting of single and multiplesubstitutions of members selected from the group consisting of halogen,nitro, nitroso, hydroxyl, carboxy, cyano, alkoxy, aryloxy substitutedalkoxy, and

wherein R, is alkyl, aryl, substituted alkyl or substituted aryl;

X is a member selected from the group consisting and CH=CH wherein n aninteger from 1 to about Y is a member selected from the group consistingof (l) 0 when M is a member selected from the group consisting ofhydrogen, ammonium, metallic cations, and amine salt residues; (2) NHwhen M is H; and (3) C=O when M is selected from the group consisting ofphenyl and substituted phenyl;

C. multifunctional carboxylic acids of the general formula:

wherein R is selected from the group consisting of:

where if R l) or (2) and R, is hydrogen, R is selected from the groupconsisting of halogen, nitro, aryl, substituted aryl, hydroxyl,

where if R #3)R, and R may be hydrogen, halogen, nitro, carboxyl, aryl,substituted aryl, alkyl and substituted alkyl n and m are integers whichmay be the same or different and where R, is H, R, may be hydroxyl D.carboxylated polymers in the free carboxyl form as describedhereinafter;

E. compounds of the formula wherein l. R, is CH -(CH and n is an integerranging from about 1 to about 19 then R, may be H, R, or R, with adifferent value for n 2. R, and/or R may be unsaturated hydrocarbonresidues 3. R, and/or R may be aryl or substituted aryl 4. R, mayrepresent atoms of a polymeric structure in which case R may be H or asotherwise defined above; and

M may be H, NH, or an alkali metal cation; and

F. polymeric structures having a repetitive substituent capable ofcontributing a negative charging influence, as defined in greater detailhereinafter.

According to the preferred embodiments of the present invention thefollowing members of the various groups of charge control agents A-Fhave been found most effective in the manufacture of photosensitivematerials in view of their relatively less positive charging propensity.Of course, any of the members of these groups as well may also be usedto enhance surface charging characteristics as described above. Themembers include:

A. those compounds wherein A is a partially and even more preferably acompletely fluorinated chain;

B. the sodium and potassium salts of the substituted benzene sulfonicacids;

C. multifunctional carboxylic acids such as citric, tartaric, succinic;

D. compounds having the following general structures:

COOH COOII wherein Z may be wherein R is lower alkyl, and

wherein R is lower alkyl, halogen, hydroxyl, nitro etc.;

III.

where R is H or methyl;

wherein Z represents the atoms necessary to complete: (a) a polyester(Le, a diol residue); (b) a polyamide; (c) polycarbonate, etc., and n isan integer from 1 to 4',

IV. CH CH wherein n is an integer from 1 to 4; and

V. polymers containing both hydroxyl and aromatic carboxylic acidgroups;

E. lower alkyl phosphates; and

F. repetitively halogen, nitro and hydroxyl substituted polymers.

Carboxylated polymers of the type described in D above have been used intheir salt forms as conductivity agents, however, we have found that theuse of carboxyl containing polymers in the free carboxyl form providethe desired negative charging influence in gelatin photographicmaterials. Such materials cannot, however, be used as conductivityagents in this form since the surface electrical conductivity thereof isfar too low for practical purposes. Furthermore, the salt forms of thecarboxyl containing polymers do not show the highly desirable negativecharging influence of the free carboxyl groups.

Among the materials included in Class E described above are severalwhich are useful as coating aids or conventional surfactants, however,when used as charge control agents in the context of this applicationthe concentration levels are generally below on the order of 0.1 gram ofester per gram gelatin or 4 micrograms per square centimeter.

Insofar as the members of group F above are concerned it should be notedthat copolymers containing substituent groups capable of influencing thecharging properties of polymeric materials in a negative direction toany desired level by varying the ratio of negative charging substituentspresent a myriad of possibilities all of which cannot be recorded here.

The following is a partial list of the specific compounds from among theaforementioned classes which have demonstrated the effects desired:pnitrosophenol sodium salt; p-aminobenzoic acid; pnitrobenzoic acid;2,4,6-trinitrobenzoic acid; sodium benzoate; p-nitrophenol; picric acid;trinitroresorcinol; p-nitrobenzene sulfonic acid; 3- nitrophthalic acid;ggitrogi inamic acid; dih benz ene phosphonate p-nitrobenzene sulfonicacid, sodium sari, p-nitrophenylacetonitrile; p-nitrophenylacetic acid;p-nitrophenoxy acetic acid; 3-nitrochalcone; 2 ,-dinitrothymol; 2,4-dinitro-1- naphthol-7-sulfonic acid; 4-nitrophthalic acid;p-nitrobenzamide, 2,4,6-trinitrobenzene sulfonic acid; m-nitrobenzenesulfonic acid, sodium salt; p-nitrobenzene sulfonic acid, dibutylaminesalt; 4-chloro-m-toluene sulfonic acid; p-fluorobenzene sulfonic acid;p-toluene sulfonic acid (hereinafter pt.s.a.), p-chlorobenzene sulfonicacid, sodium salt;,

p-bromobenzene sulfonic acid, sodium salt; 2,5-

dichlorobenzene sulfonic acid; p-hydroxybenzenesulfonic acid, sodiumsalt; o(carboxy methoxy) benz oic acid; p-hydroxy b enzoic acid;p-chlorophenylacetic acid; 4,4'-biphenyl disuli'onic acid;2,5-dichlorosulfanilic acid, sodium salt; sulfosalicyclic acid;4-sulfophthalic acid, mono sodium salt; 2,2-diphenic acid; trimelliticacid; benzene sulfonic acid (hereinafter b.s.a.); b.s.a., didodecylaminesalt; b.s.a., dibutylamine salt; p-t.s.a., tridodecylamine salt;p-t.s.a., p-t.s.a., tridodecylamine salt; p-t.s.a., didodecylamine salt;p-t.s.a., triethylamine salt; 4-sulfophthalic acid, dibutylamine salt;b.s.a. tridodecylamine salt; b.s.a., tributylamine salt; p-t. s.a.,:triethylamine salt; p-t.s.a., tributylamine salt; pyromellitic acid;terephthalic acid; phthalic acid; mellitic acid; citric acid; salicyclicacid; d-tartaric acid; succinic acid; oxalic acid; malonic acid; malicacid; maleic acid; adipic acid; fumaric acid; hydroquinone; glutaricacid; I- tartaric acid; 50-50 d-, l-tartaric acid; pyromellitic acid,mono sodium slat; l,3-dicarboxymethyl-5 benzenesulfonic acid, sodiumsalt; pyromellitic acid NH, pH 4.3; pyromellitic acid Nl-L; pH 8.2; 5-sulfoisophthalic acid sodium salt; 5-sulfosalicyclic acid, trimelliticacid, trimesic acid, compounds of .the following empirical formulascellulose acetate phthalate, hexahydrophthalate, trimelitate etc.,poly(vinyl chloride), poly(vinylidene chloride), poly(chlorostyrenes),poly(nitro styrenes), poly(vinyl phenols), poly(vinyl chlorobenzoate),poly( vinyl nitro benzoate), and poly( vinyl nitro phthalate).

Among the photographic products which have demonstrated the most problemwith triboelectric effects are X-ray and Aero film materials. Due to thepeculiar nature of the internal and external environment of each ofthese classes of photosensitive products they provide especiallydifficult problems whose solutions are critical to the production of thehigh resolution, extremely high quality presently demanded in themarkets for these products. Utilizing the techniques of the instantmethod, promising products have been developed in each of these areasand these are described individually hereinafter as a non-limiting meansof defining operative techniques, compositions and structures embodyingthe successful practice of the instant invention. X-Ray Materialsdidodecylamine salt;

In the manufacture of X-ray materials at the high coating speedsdescribed earlier, considerable discharge generally occurs. It is inproducts of this nature that gel pickoff due to relatively high humidityconditions in the coating machine becomes prevalent. In

an attempt to solve these problems, measurements were made using wellknown techniques to determine the maximum amount of triboelectriccharging which could. be tolerated on a single impact between a gelsubbed X-ray polymeric base and stainless steel and anodized aluminumrollers used to transport the subbed base through the coating machine.This analysis indicated that a maximum single impact charge of about -12esu/cm was the most which was tolerable, since above this level at thelow humidities required to prevent gel pickoff, even with conductivityagents, the eumulative charge built up could not be drained off fastenough and eventually resulted in destructive and often equallyspectacular static discharges in the coating machine on the order of 2feet in length! This maximum or threshold level of single impact chargewill of course vary depending upon the number of rollers in a givenmachine, machine speed, relative humidity, etc.; however, it will betaken as a target level for purposes of the instant discussion.

Thus, the immediate problem becomes one of maintaining the single impactcharging level below about 10 esu/cm.

Using the techniques and data presented above, it was determined thatcompounds of class B described hereinabove were best suited to controlof static in the internal environment of this material and small amountsof these compounds were incorporated into these X-ray products.

As already indicated hereinabove, the charge control agents of thepresent invention can be incorporated into the surface whose charging isto be controlled in a number of fashions. In the instant case it wasdecided that overcoating the problem-causing gel sub layer with a thincoating of on the order of from about 0.2 to about 4 micrograms/cm ofthe charge control agent" by deposition from a suitable solvent systemsuch as ethyl alcohol provided most satisfactory results. Of equalsuccess is the technique of mixing the charge control agent with the gelsub prior to coating thereof.

When this latter technique was used, because the materials of group Bare not strong surfactants, it was found necessary to increase theconcentration thereof to a level of from about 0:5 to about 1.0 g/g ofdry weight gelatin in order to obtain a sufficiently high surfaceconcentration thereof to give the desired surface chargingcharacteristics when the subbed base was impacted with stainless steeland/or anodized aluminum rollers. A third method for incorporating thecharge control agent comprises contacting a solution thereof with thesurface to achieve adsorption thereto and then removing any excess. Thismethod was found most successful when the charge control agent" solvent,for example lower alkanols such as methyl, ethyl, etc., alcohols, was,or incorporated, a swelling agent for the gelatin which opened the poresof the gel surface to permit penetration therein, thereby insuring (a)the formation of at least a discontinuous layer of the charge controlagent" at the surface of the gelatin; and (b) the secure attachment ofthis layer to the gel.

Preferred materials for this type of application are specified in theExamples presented below.

Aero Film A second photosensitive product which has demonstrated aninordinately large degree of charging problems is aero film. Theproblems associated with these materials are due in large part to thepeculiar external environment in which they find use. These materials Iare used under extremely severe humidity conditions at extremely highaltitudes and are required to advance at high speed through cameraswhose component parts of rubber and plastic almost seem designed withthe ultimate goal of generating as much static as possible on the filmrun through them.

In most of the aero film cameras, the rollers ther stainless steel,anodized aluminum, plated metals or several varieties of elastomericmaterials, and stataic generated static clue to the impacting of eitherthe emulsion side or the rear surface of the film with the roller. Thus,the surface of the photosensitive product which must be modified iseither the emulsion side which is generally overcoated with a protectivelayer of for example, gelatin plus a coating aid, and the backing layerwhich may include a slip agent and in present conventional materials aconductivity agent of the type described above.

In the modification of this type of product it was sought to incorporatea surfactant type of material to achieve the lowest possible bulkconcentration of charge control agent in the emulsion overcoat and- /orbacking layers. Thus, the materials of class A, described above, wereselected as the primary candidates for use in this application, althoughmembers of each of the other classes could also be used.

Among the materials of class A which were preferred in this context werethose wherein A (described above) was a partially or completelyfluorinated carbon chain, Z is selected from the group consisting of andX is a halogen. The most useful member of this class and that which todate has demonstrated the strongest negative charging propensity whilebeing readily available had the following formula:

and whose utility is indicated in the Examples below.

In the evaluation of photosensitive materials for use in aero filmapplications one becomes almost immediately aware of the limitationsplaced on'any charge control system by the character of the externalenvironment; i.e., a single film product may find use in as many asperhaps different cameras all of which have different roller surface,numbers of rollers, advance speeds, film orientations, etc. Since eachof these variables modifies to some degree one or more of thosecharacteristics which determine impact electrification (alreadydescribed above) it becomes apparent that are eione specificconcentration of a charge control additive which gives adequateprotection when the film is exposed in camera X under its peculiar setof conditions may perform relatively poorly in camera Y whose rollersare of a different material, whose speed is faster and which is designedfor use at a higher altitude. Thus, the addition of charge controlagents is not a panacea in this field of use and, indeed, in certainapplications must be supplemented by the addition of conductivity agentsto compensate for other modes of charging by bleeding off charges whichif not bled off could result in the build up of acharge above thedischarge threshold levels. In such applications, it has therefore beenfound useful to combine the charge control agents of the instantapplication with conductivity agents to obtain insurance againstexcessive charge build-up.

Although easily stated, the result is not always so easily defined in agiven system, since conductivity agents like all other materialsdemonstrate their own peculiar impact electrification characteristicswhich must also be accounted for.

Mixtures of charge control and conductivity agents thus may be used toprovide impact electrification values close to zero over a wider rangeof concentrations. Furthermore, combinations of two or more chargecontrol agents" may be used to achieve finer tuning" of the surfacecharging characteristics of any given modified surface.

The following Examples will serve to better demonstrate the techniquedescribed above, a broad variety of useful charge control agents" aswell as radiation sensitive products incorporating charge control agentsof the type described.

EXAMPLE 1 A standard test surface is prepared by coating 7 milpoly(ethylene terephthalate) support with an unmodified overcoat ofgelatin to a dry weight of l mg/cm Coated samples are conditioned to 5%RH 70F. A solution containing 1 mg/ml of the test compound in ethylalcohol is prepared and one drop of this solution allowed to spread over4 cm of the gelatin test surface. The resultant coverage of testcompound on the gelatin surface is approximately 4 ug/cm". This testarea is then impacted with the metal test head (or other referencematerial) in the apparatus and with the technique described in theaforementioned Bailey patent and the charge generated is recorded. Insome cases unsubbed poly(ethylene terephthalate) is used as a testsubstrate. The test values are recorded in Table I. In should also benoted that other solvents may be used in some cases for appropriatesolvent action.

The values in Table I must be considered as relative values. Thecleaning procedure for the impacting head may leave some surfacecontamination thus changing the magnitude of the charge generated onimpact. Cleaning procedures have evolved over a period of time, however,and a much more repeatable surface is obtained by cleaning withappropriate solvent for the material previously tested followed bycleaning with absolute alcohol. Cleaning in this manner produces a valueof approximately +30 esu/cm against the untreated gelatin check. Thus,the values in Table 1 must be compared with the appropriate chargingvalue ob-,

Table I Impact Charge Values for Treated Gelatin Against VariousReference Surfaces Esu/cm at 20 psi Impact Pressure Reference SurfacesNo. Surface Treatment Solvent Metal Rubber Rem .let

l Sodium p-Nitroso Phenol ETOH 3.4 7.5 LI 2 pAmino Benzoic Acid do. 3.l+l l.l .4 3 p-Nitro do. do. do. l9.2 O 3.3 Check. untreated gel. Avg.do. 05.9 +l2.6 3.5

4 Benzoic Acid ETOH 2.] +l 1.4 3.2 5 2-4-6 Trinitro Benzoic Acid do.28.8 l5.3 5.4 6 Sodium Benzoate do. 5.l 8.7 .7 7 p-Nitro Phenol do. 8.]+102 3.2 8 Picric Acid do. 24.7 +l 1.3 3.0 9 Trinitro Resorcinol do.36.(] -l3.7 4.0 Check, untreated gel, Avg. do. 3.5 +l2.l 4.5

10 P-Nitro Benzene Sulfonic ETOH 32.0 l7.7 4.0

Acid ll S-Nitro Phthalic Acid do. 27.3 3.8 2.7 l2 p-Nitro Cinnamic Aciddo. l5.6 l4.l 5.6 Check, untreated gel Avg. do. 4.3 +l2.4 4.l

l3 Benzene Phosphonatc. diH ETOH 2.6 +1 L8 2.4 l4 Ethyl diH Phosphatedo. l3.0 3.7 0 l5 Butyl diH Phosphate do. l2.5 L2 0 l6 Dihutyl HPhosphate do. L3 0 0 Check. untreated gel. Avg. do. 6.8 +l L) 4.1

17 p-Nitm. NaBenzcne Sulfonatc ETOH 32.l Check. untreated gel. Avg.

l8 p-Nitrophenyl Acetonitrile ETOH .l 8.0 19 P-Nitrophenyl Acetic Aciddo. 13.4 1.9 20 p-Nitrophenoxy Acetic Acid do. 2o.7 7.6 2l3-Nitrochalcone do. .4 +l l.5 Check. Avg. untreated gel 8.1 +l2.0

Table I Csmti ss Impact Charge Values for Treated Gelatin AgainstVarious Reference Surfaces Esu/cm at psi Impact Pressure ReferenceSurfaces No. Surface Treatment Solvent Metal Rubber Rem Jet 222.6-dinitro thylmol ETOH -l 8.4 4.0 23 2.4-dinitro-l-napthol-7-Sult'onic Acid do. 23.0 l3.l 24 4-Nitrophthalic Acid do. 39.6 --l2.0 25p-Nitrohc'nzamidc do. 4.3 .5 Check. Avg. untreated gel 9.2 +l0.5

26 24-6 Trinitro Benzene Sulfonic Acid ETOH 39.0 7.1 Check. Avg.untreated gel 9.7 8.9

27 m-Nitrn Sodium Benzene Sulfonate ETOH 29.0 6.0 Check, Avg. untreatedgel +l2.l 6.0

"' Carbon dispersion in cellulose acetate hexuhydrophthalate lmpactCharge for Treated Gel and Polyester Strips Esu/cm" at 20 psi ImpactPressure Metal Reference The following abbreviations are used: B.S.A.fur Benzene Sull'unic Acid p-T.S.A. for p-Toluene Sulfunic Acidpnlytcthylenc terephthalute) No. Surface Treatment Solvent Gel Polyester28 p-Nitro B.S.A., dibutyl amine salt ETOH -24.0 29 p-Nitro B.S.A..dibutyl amine salt PrCl, 3.0 30 p-T.S.A. ETOH l8.6 20.5 Check, Avg.untreated gel 8.1

3| 4-Chloro m-Tolunc NaSulfonate ETOH 3.0 3.0 32 p-Fluoro Sodium BenzeneSulfonate do. 22.0 l4.0 33 p-Chloro Sodium Benzene Sulfonatc do. 35.022.0 34 p-Bromo Sodium Benzene Sulfonate do. l0.0 8.5 Check. Avg.untreated gel and Mylar 35 2.5-dichlom B.S.A. ETOH 5.0 8.0 36 p-HydroxySodium Benzene Sulfonate do. 220 l5.5 37 o-(carboxy methoxy) BenzoicAcid do. -35.0 24.5 38 p-Hydroxy Benzoic Acid do. 30.() l0.0 Check. Avg.untreated gel and Mylar +l0.0 .3

39 p-Chloro phenyl Acetic Acid ETOH l3.0 .6 40 4.4-Biphenyl disull'onicAcid dd. 37.0 l8.0 4| 2.5-Dichloro Sulfanilic Acid.

Na salt do. l3.0 2.0 42 Sulfosalicylic Acid do 45.0 36.0 Check. Avg.untreated gel and Mylar 43 4-Sulfophthalic Acid, mono Na salt ETOH 25.0l6.0 44 2,2'-Diphenic Acid do. I l.0 3.0 45 Trimellitic Acid do. 32.028.0 Check. Avg. untreated gel and Mylar +l0.0 .4

46 Benzene Sulfonic Acid ETOH 32.0 .4 47 B.S.A.. didodecyl amine saltdo. 3.2 2.0 48 Benzene Sulfonic Acid PrCl 22.0 1.2 49 B.S.A., didodecylamine salt do. 3.7 2.4 Check, Avg. untreated gel and Mylar 9.5 .4 50B.S.A., dibutyl amine salt PrCl, 3.0 1.] 5| p-T.S.A.. triodecyl aminesalt ETOH 2.0 3.1 52 p-T.S.A., didodecyl amine salt do. 4.2 3.3 53p-T.S.A.. tridodecyl amine salt PrCl, 3.0 1.7 54 p-T.S.A.. didodecylamine salt do. 6.7 2.0 'Check. Avg. untreated gel and Mylar +l3.0 .5

55 p-T.S.A.. triethyl amine salt ETOH +350 +350 56 4-Sulf0phthalic Acid.dibutyl amine salt do. l4.0 l4.0 57 B.S.A. tridodecyl amine salt do. .8.8 58 B.S.A.. tridodecyl amine salt PrCl, 3.0 L5 59 B.S.A.. tributylamine salt MeOH +l4.0 +l6.0 Check. Avg. untreated gel and Mylar +l0.5l0.5

of simple structure in mixture with the gelatin. A greater quantity ofagent is necessary, however, than if it were applied to the surface.Mixtures in gelatin are spread or coated by hand on cellulose acetatepropionate (14 percent propionyl, 30 percent acetyl plasticized withbutyl sebacate), also subbed with a conventional gel-nitrate solution (1percent gel, kpercent cellulose nitrate [l 1% N 2 percent acetic acidbalance methanol and acetone), as a simulated gel wash. The chargingvalues are shown in Table ll.

-Continued Impact Charge for Treated Gel and Polyester Strips Esu/cm at20 psi Impact Pressure Metal Reference No Surface Treatment Solvent GelPolyester" 60 B.S.A., triethyl amine salt MeOH +1 1.0 2.2 6| p-T.S.A.,triethyl amine salt do. 2.! 9.0 62 p-T.S.A., tributyl amine salt do.+23.0 8.5 Check, Avg. untreated gel and Mylar +1 1.0 .4

63 Pyromellitic Acid MeOH -40.0 5.5 64 Terephthalic Acid do. +l8.0 l0.065 Phthalic Acid do. +20.0 4.0 66 Phthalic Acid ETOH 34.0 15.5 Check,Avg. untreated gel and Mylar +l3.0 .6

67 Mellitic Acid MeOH -40.0 8.0 68 Citric Acid ETOH 32.0 69 SalicylicAcid dd. 3.0 70 d-Tartaric Acid do. 33.0 l6.0 7l Succinic Acid do. -l4.0-l0.0 72 Oxalic Acid do. 1.0 -12.0 73 Malonic Acid do. +l2.5 7.0 74Malic Acid do. l6.0 4.0 75 Maleic Acid do. 19.0 14.0 70 Adipic Acid ddv6.0 4.0 77 Fumaric Acid dov l6.0 2.5 78 Hydroquinone do. l.0 9.0 79Glutaric Acid do. 1.6 80 L-Tartaric Acid do. 40.0 24.0 8| 50-50L-Tartaric Acid dd. 40.0 82 Pyromellitic Acid, Mono Na Salt do. l5.0 83l,3-dicarboxymethyl--Na benzenedo. l.6 4.0

Sulfonate Treated Sub Strip 84 Pryomellic Acid NH+ 4.3 l% in H2O 4.0 85Pyromellitic Acid NH} pH 8.2 do. +l3.0

Treated Sub Strip 86 Mellitic Acid 00 McOH- 1.4

40 H 87 Citric Acid MeOH L8 88 Citric Acid 60 MeOH- .6

11,0 89 d-Tartaric Acid MeOH .25 9t) d-Tartic Acid 60 MeOH- .4

40 H2O 9| Pyrnmellitic Acid 60 MeOH- .9

40 H20 92 S-Sulfoisophthalic Acid Nu salt MeOH 7.0 )3 S-SuIfoiisalicyIicAcid MeOH 1.2

' polytclhylcnc tcrcpthulutc) Several of the test materials are alsoapplied from wa- Table ll ter. The molecular size of many of the simplercompounds no doubt allows them to be absorbed into the Simulated GelWash Test swollen gelatin coating since it contains no hardener. 30 'PS'ded F Stainless Steel Reference Head Some materials may also beimbibed into the surface values in on imed Ge mi S bs during longerperiods of time at conditions of high rela- G I A R tive humidity whichallows considerable swelling of the Agent m e gem :2 gelatin coating.Thus, these materials are no longer present at the surface (unless theyare surface active None Sub Check +210 d h rf h f None Untreated Type Vgel check +l7.0 -materrals) an t e su ace is now c aracteristic 0 an 94ssmmancyuc Acid +5.0

untreated gelatin. 9s Pyromellitic Acid +3.5 -2.0 W 96 Tamol N 4 97Mellitic Acid 9.0 98 Citric +4.0 EXAMPLE 2 99 Sapomn .2

conslderlflg the pracflcahty of modlfymg the charg' Inspection of thesevalues shows a considerable reducf g P PPF of f Surfaces from aqueousSolu' tion in the high positive charging behavior of gelatin. trons, it15 also possible to coat a charge control agent EXAMPLE 3 A machinecoating is made from the data of Example 2 to control average andinvestigate other reference surfaces and other humidities. The coatingsolution consist of:

1 percent and 1.5 percent Pyromellitic acid (PMA) 1 percent Type V gelThe PMA and gel check also contain 0.19 percent Saponin as a coatingaid. The five solutions are coated by conventional hopper application at(a) 123, and (b) 154 cc solution per 100 ft coverages on both cellulosetriacetate (41 percent acetyl) and cellulose acetate propionate (14percent propionyl, 30 percent acetyl) support, subbed with a mixedgel-nitrate sub. The samples are then impacted with two referencesurfaces, stainless steel and rem jet. The values are shown in TableIII. The charging values for both sets of experimental samples areidentical.

Table III Gel Wash Coatings On Cellulose Acetate Propionate Gel NitrateSub (Described Above) ESU/CM On Sub Against Metal and Rern Jet 20 PS1Single Sided Impacts 5% 50% Sample 5% Rem Rem Rem No. Feature CoverageMetal Jet Jet" Jet Sub Check-uncoated +30.0 +5.9 +5.5 +5.8 1 check 1%Type V Gel I23 +3.8 +3.2 +3.7 +3.6 2 Check 1% Type V Gel I54 +2.0 +2.4+2.9 +3.4 7 1% Gel I; PMA 123 l.2 .52 +1.] .87 6 17r Gel l7r PMA 154 2.0.5 .8 .4 9 1% Gel 1.5% PMA 123 2.0 .52 .l .5 l0 1% Gel 1.5% PMA 154 3.2.2 .03 .4 l6 1% Gel Sap. 123 +2.0 +1.4 +2.4 +3.2 14 1% Gel 1% Sap. 154+1.0 +1.2 +2.1 +2.7 18 1% Gel 1.5% Sap. 123 .3 +1.3 +2.0 +2.6 20 1% Gel1.5% Sap. 154 +1.0 +1.1 +2.4 +2.0

Carbon dispersion in cellulose acetate hexahydrophthulate Inspection ofTable "I shows PMA is clearly more effective than Saponin and isrelatively invariant of the humidity range whereas Saponin shows apositive trend (less effective) with humidity. The lower values obtainedfor check samples 1 and 2 are the result of 0.19 percent Saponin used asa coating aid.

EXAMPLE 4 Many of the smaller organic molecules of Example 1 are easilyimbibed into a gelatin surface if they are applied from aqueous mediadue to the swelling of the gelatin. Thus the resultant chargingproperties of the surface may be difficult to control. A large moleculeincapable of excessive imbibition yet retaining the inherent chargingproperties is prepared as follows: A copolyester (polyethylenepyromellitate) is prepared by mixing in a suitable flask equimolaramounts of ethylene glycol and pyromellitic dianhydride with sufficientN,N-Dimethylformamide (DMF) to provide a homogeneous solution at 60C.The temperature is then raised to 90C and DMF distilled off under avacuum. Heating is continued under vacuum ultil the temperature of thecontents reaches 175C. This temperature is maintained for approximately1 hour.

A viscous off-white polymer remains which upon cooling solidifies into aglassy mass. The polymer is hard and brittle, dispersible in water, andsoluble in dilute alkali.

Polyethylene pyromellitate may be coated from aqueous solutions overgelatin with retention of the negative charging characteristic of themolecule. A 1 percent aqueous solution coated on the gelatin sub of acellulose acetate support (43.3 percent acetyl, plasticized with methoxyethyl phthalate and triphenyl phosphate) produces a charging value of-33 esu/cm 20 psi impact at 5% RH.

Mixtures of gelatin and polyethylene pyromellitate can be preparedsubstantially as described in Example charging value for the untreatedsample under identical conditions is +30 esulcm The charging propertiesof gelatin may be modified by chemical reaction of the gelatin.Representative modifications are shown in Examples 5 and 6.

EXAMPLE 5 Twenty gm. of acid process gelatin is dissolved in 100 mlwater and 100 ml DNF added. The solution is heated to C and 5.0 gm.B-Propiolactone is added with vigorous mixing. The temperature ismaintained for one-half hour, the contents cooled, and precipitated intoa 1:1 mixture by volume of acetonemethyl alcohol. The precipitate isthen extracted with 3A alcohol in a Waring blender and finallytriturated overnight with 3A alcohol, filtered, and dried. The dry yieldis 24.9 gm.

The chemically modified gelatin is soluble in water. A 6 percentsolution forms a gel at room temperature.

A 6 percent solution coated 3 mils wet thickness over subbed cellulosetriacetate produces a dominant surface of modified gelatin. The impactcharge value of this surface is +6 esu/cm. The charging value of thesubbed cellulose triacetate is +30 esu/cm".

EXAMPLE 6 Another chemically modified gelatin with modified chargingproperties is prepared as follows:

Forty gm. acid process gelatin is slurried in 250 mls dry DMF. To this,19.2 gm (0.! mole) trimellitic anhydride (TMA) dissolved in 50 ml DMF isadded. The mixture is thermostatted at 50C with mixing for a period of30 hours during which time the gelatin reaction product graduallydissolves to produce a homogeneous solution. The solution is colled andprecipitated into 1,500 ml isopropyl alcohol. Subsequent washing withisopropyl alcohol and drying yields 50.1 gm or 84.6 percent of thetheoretical amount. The remainder is lost due to solubility in theisopropyl alcohol DMF mixture.

The product has limited water solubility but is dispersible in water.Coatings made from a 6 percent dispersion produce a matte coating.

A 6 percent dispersion has a pH of approximately 2. Upon addition ofalkali to a pH of approximately 4 a clear solution results.

The impact charging values of this material depend upon the state of thecarboxyl groups on the modified gelatin. In the free carboxy form thematerial is less positive charging than unmodified gelatin, however, asthe carboxyl groups are neutralized with various alkalies the chargingproperties more closely resemble those of unmodified gelatin. Sixpercent solutions of TMA modified gelatin are coated over cellulosetriacetate at various pH's and impact charging measured at 20 psi and 5%RH. The results are shown in Table IV below.

TABLE IV lmpact Value pH Alkali esu/cm" 2 None +l 4 4 NaOH +30 4 NH OH+16 8.5 NH 0H +19 unmodified gelatin +30 The reduction of positivecharging of gelatin by the above chemical modifications is notsufficient to eliminate static completely, but is only intended to showrepresentative chemical modification with active negative charginggroups on the gelatin backbone. Other negative charging groups could beintroduced which might be more effective. A chemically modified gelatinis of value however. Mixtures of a chemically modified gelatin with anegative charging material to reduce charging close to zero requires asmaller amount of addenda. This is of particular value if the addenda issensitometrically active or very costly and can only be used in limitedconcentrations.

Although the principal subject of surface modification described in theforegoing examples is gelatin, it should be clear that since allmaterials demonstrate triboelectric effects to one degree or anotherthat virtually any charging surface can be modified with an appropriateagent to produce desired surface charging characteristics.

EXAMPLE 7 A suitable support poly(ethylene terephthalate), celluloseester, etc.) is first coated with an unmodified 5 percent gelatinsolution at a wet coverage of 615cc per hundred square feet. Thisgelatin coating provides an isolating layer over which the subsequentlyprepared experimentally modified gelatin can be coated. A 2.9 percentsolution of gelatin is prepared using low concentrations of afluorinated surfactant having the formula and this modified gelatinsolution simultaneously overcoated at a wet coverage of 176cc perhundred square feet. The samples are then equilibrated at 5% RH, F forthe impact electrification measurements. Impact values are measured at5% RH, 70F and 20 psi impact pressure. The results are shown in Table Vbelow.

Coverage A equals 175 cc solution per l00 ft Coverage B equals 350 ccsolution per ft Inspection of Table V will show that the two differentthicknesses are zero charging at 0.025 and 0.015 gm per lb. for A and Brespectively. Coverage B is within the 0 i 8 esu/cm in the concentrationrange of 0.012 to 0.02 gm per lb.

Coatings of other materials tested in a fashion similar to that just asdescribed are shown in Table VI below wherein the concentration of theadditives is in percent by weight and the coverage is Coverage A, 10PS1, 5% RH, 70F).

T l yLlQ n i u d on +5.5 +6.6 +6.2 +4.8 1eHa:-OPOK +10 +2.9 +2.4 +1.0+1.3 +0.0 Cn 1i= oHr1O-P0H /OH +10 +1.4 +1.6 +1.2 +1.2 CnHzE-OP EXAMPLE8 within whatever limits are necessary. It also allows the TABLE VIIImpact electrification Saponin-fluorocarbon Surfactant MixturesFluorocarbon Saponin Concentration Concentration gm/lb of melt gm/lb ofmelt 0.|0 0.80

Comparison of Tables V and VII shows the expansion of effective workingconcentrations for the fluorocarbon by using a mixture of charge controlagents and coating aids. With these types of combinations of materialsthe charging characteristics of a particularsurface use of the bestavailable surfactants used as coating aids such that the quality of thecoating is not compromised to control static.

Many other combinations of surface active agents may be employed insubbing layers, backing layers, emulsion layers and in coatings overemulsion layers to control the charging properties of these individuallayers and the ultimate product.

EXAMPLE 9 A similar result is observed in the treatment of the X-raymaterials described above, although such dual protection is notnecessarily so important with that type of product in view of therelatively controlled external and internal environment of theseproducts.

Coatings of the X-ray subbing layer are made in conventional coatingapparatus to investigate suitable concentrations of charge controlagents and mixtures thereof. A conventional gel subbing layer, is usedexclusive of the conducting salt.

The sub is normally composed of one per cent gelatin, Saponin, afungicide, a hardener, for example chrome alum and matte.

The effect of Saponin additions to the subbing composition is shown inTable VIII below:

TABLE VIII Impact Electrification of Modified Subbing Layers vsStainless Steel and Anodized Aluminum at 20 psi Impact Pressure, 70F

Total 5% RH RH Sample Saponin Anodized Anodized No. Addendum SS AluminumSS Aluminum 1 O +28.0 +l2.5 +26.0 +l6.0 2 .0l +24.0 +1 l.0 +220 +l2.7 3.l5 5.9 6.0 8.4 2.4 4 .20 2.0 3.5 0.3 L0

5 .25 1.6 2.2 4.2 L8 6 .30 3.0 0.8 5.0 3.2 Conventional xray product+l6.5 +l0.5 +l7.0 7.3

Inspection of Table VIII indicates that the higher concentrations ofSaponin could be used successfully to lower the charging characteristicsof the sub. However, at concentrations of 0.25 per cent or above thereare indications of destruction of good bonding properties of theemulsion layer.

Mixtures of Saponin and p-chlorobenzene sulfonic acid sodium salt,p-CSA, Na Salt, were used as the subbing addenda and coated and testedas above. These results are shown in Table IX below.

TABLE 1x Percent Addenda 5% RH 50% RH p-CSA. Anodized Anodized SampleNo. Saponin Na Salt SS Aluminum SS Aluminum 7 .0l .4 +l6.0 9.0 22.0 9.08 .0] .45 7.2 2.6 2S.0 l0.0 9 .0l .5 9.5 6.5 27.0 l3.3 l .l0 .45 +l3.89.0 8.0 5.4 ll .IO .50 +5.0 2.5 -8.0 l.2 l2 .l0 .60 5.0 l.2 ll.7 5.0 l3.IO .70 5.0 2.5 l0.0 5.0 I4 .l3 .50 +5.3 +1.2 ll.4 -6.0 l5 .IS .50 2.61.0 l2.0 8.0 l6 .l8 .50 +5.4 +0.8 6.0 "4.0 l7 .13 .60 4.2 5.l l4.4 8.5l8 .l5 .60 5.6 4.9 l4.0 7.0 l9 .l8 .60 2.5 4.5 9.0 4.5 Check +l6.5 +l0.5+l7.0 7.3

In Trial l the emulsions are coated in the normal manner, i.e.. one sideis emulsion coated and dried then the other side is emulsion coated inline and dried.

ln Trial 2 the first emulsion is coated and dried and put through towindup. The roll is then sent through the machine a second time toemulsion coat the opposite side. Thus, Trial 2 is a much more severetest of the electrostatic sparking propensity of the sub layer.

The results are shown in Table X below:

TABLE X Production Trials of Saponin (p-C.S.A., Na salt) Addenda topoly(ethylene terephthalate) subs Impact Electrification of Sub 5% RH RHAnodized Anodized Addenda SS Aluminum SS Aluminum Static Results 0.2%Saponin Trial 1 +5.5 +5.4 +l3.0 +5.7 Scattered Branch 0.0% pstatic, 30ft. only;

chlorobenzenesulfonic remainder clear Acid Sodium Salt no static Trial 2+5.5 +l2.5 Branch Static from roller grooves, some spot staticthroughout 0.9? SaponinTrial l +8.5 +9.5 +l6.0 +6.0 Scattered spotstatic 0.45% p-CSA Na Salt Trial 2 +1 l.0 +l0.() Spot static throughout0.2% Saponin Trial l +l2.0 +9.0 +23.0 +8.4 No static marking 0.45% p-CSANa Salt Trial 2 +l5.0 +l8.5 Slight static. branch and spot for 30 feetonly Check Trial l +23.0 +l2.2 +24.0 +l4.0 No static marking Trial 2Spot static throughout Trial 2 Dense branch throughout for controllingthe charging characteristics of the surface is obtained since narrowervariations in charging behavior are experienced with similarquantitative additions of charge control agent.

EXAMPLE l0 Two production coatings of Saponin p-chlorobenzenesulfonicAcid Sodium Salt (p-CSA, Na Salt) are used as addenda in subbingmixtures and coated. Full width samples are processed and examined forstatic defects.

a 33 Table Xl Production Rolls of Saponin p-CSA, Na Salt Addenda toPoly(ethylene terephthalate) Sub (Gelatin Plus Matte, Fungicide, Etc.)

Impact Electrification H Two of the above full length rolls wereemulsion coated in the normal manner and subsequent processing showedboth to be free of static. Emulsion adhesion is good and there is nogelatin pickoff due to tacky subbing layers during emulsion coating.

It is important to note that all but one sample produced on theproduction machines are very close to the general criteria of i esu/cmagainst anodized aluminum on production coatings. For any given productthis limit may be subject to broader or possibly narrower limits.

A further review of Table 1X will show that'there is sufficient room foradjustment of concentration to reduce charging very close to zero.

Additions of p-CSA, Na Salt to subbing formulations at 1x and 10X use.concentrations have shown no adverse sensitometric effects onaccelerated testing.

Although the foregoing description relates primarily to testing andtreatment of gel subbed'and unsuhbed polymeric film base materials itshould be clear that the techniques and principles disclosed herein areequally applicable to other materials which demonstrate undesirabletriboelectric effects. For example, resin coated paper products whichfind broad usage in the photographic arts can be similarly tested andthe various surfaces thereof treated in accordance with the techniquesdescribed herein. Subbing layers applied over such bases may also betreated as may emulsions, non-silver, and therefore nongelatin,photosensitive products, etc.

Furthermore, although the description contained herein has been directedprimarily to the additionof relatively high negative charging species tosurfaces which demonstrate relatively high positive charging whenimpacted with a given reference surface which forms a greater portion ofthat surfaces internal and/or face to be modified will of course dependon many of' the numerous factors discussed hereinabove which affect thecharging of the system under consideration.

From the foregoing examples several points concerning the systems underdiscussion and the solutions and techniques proposed for use inconnection therewith should be clear. Among these are the following:

l. The static charging properties of surfaces are apparently a directconsequence of their chemical structures. In particular the strongpositive charging characteristics of gelatin and gel-nitrate subs asutilized in photographic applications can ,be "neutralized" ornullified" by the application of any one of a number of negativecharging materials out of a suitable solvent or in some other manner toform a continuous or discontinuous layer having a dry thickness of lessthan about 300 Angstroms.

2. The effect of this technique is coverage dependent thereby providinga handle" with which the charging or surface potential can be adjustedto any desired level.

3. The charging properties of any given unmodified surface, a surface ofa charge control agent" or a surface modified with a charge controlagent are impossible to predict with any degree of certainty and thus,if one desires to alter the charging characteristics of any particularsurface it is necessary to first accurately measure the chargingcharacteristics of the unmodified the present at least, involve thepractice of the method' of the present invention.

Furthermore, although, in the discussion and examples presentedhereinabove substantially all of the techniques described for overcomingthe problem of static charging have been directed to the treatment of,for example, the photographic film or more broadly the im pactingsurface it must be made clear that similar results can be achieved bytreatment of the impacted surface, i.e., for example, in the case ofaero film the camera roller or in an emulsion coating machine thestainless steel or anodized aluminum roller. Such treatment can beaccomplished by impregnating into or coating onto the surface ofsuchroller"charge control agents which produce a substantially zero, or verylow charge when impacted with, for example, a gel subbed film support,or the emulsion 'or support side of a specific photosensitive material.

Stated more generally, as described at the beginning of this applicationthe generation of triboelectric charges is due to the contacting anddissociation of two usually dissimilar surfaces. What is being statednow is that either or both of these surfaces may be treated to reducetriboelectric charging to an acceptable level. Thus, in the case of thecharging problem incident to the use of aero film, it would be entirelypossible to coat or impregnate the camera transport rollers with asuitable charge control agent to achieve charge reduction.

As should also be clear from the foregoing description the quantitiesand concentrations of charge control agents which are used to alter thecharging characteristics of surfaces will vary boradly depending uponthe nature of the charging surface and may range from a discontinuousspotty layer up to and including continuous layers of charge controlagents" which demonstrate, to a large extent, the chargingcharacteristics of the charge control agent.

The silver halide emulsions used in the photographic products of thepresent invention can comprise, for example, silver chloride, silverbromide, silver bromoiodide, silver chlorobromide, silver chloroiodide,silver chlorobromoiodide crystals or mixtures thereof. The emulsions maybe coarse or fine grain emulsions prepared by any of the well-knowntechniques, e.g., single jet emulsions such as those described inTrivelli and Smith The Photographic Journal, Vol. LXXIX, May, 1939 (pp330-338), double jet emulsions such as Lippmann emulsions, ammoniacalemulsions, thiocyanate or thioether ripened emulsion such 55 thosedescribed in Neitz et al. U.S. Pat. No. 2,222,264 issued Nov. 19, 1940;lllingsworth U.S. Pat. No. 3,320,069 issued May 16, 1967; and McBrideU.S. Pat. No. 3,271,157 issued Sept. 6, 1966. Surface image emulsionsmay be used or internal image emulsions may be used such as thosedescribed in Davey et al. U.S. Pat. No. 2,592,250 issued May 8, 1952;Porter et al. U.S. Pat. No. 3,206,313 issued Sept. 14, 1965; BerrimanU.S. Pat. No. 3,367,778 issued Feb. 6, 1968; and Bacon et al. U.S. Pat.No. 3,447,927 issued June 3, 1969. If desired, mixtures of surface andinternal image emulsions may be used as described in Luckey et al. U.S.Pat. No. 2,996,382 issued Aug. 15, 1961. The emulsions may be regulargrain emulsions such as the type described in Klein and Moisar, J. Phat.Sci., Vol. 12, No. 5, Sept./Oct., 1964, pp 242-251. Negative typeemulsions may be used or direct positive emulsions may be used such asthose described in Leermakers U.S. Pat. No. 2,184,013 issued Dec. 19,1939; Kendall et al. U.S. Pat. No. 2,541,472 issued Feb. 13, 1951;Berriman U.S. Pat. No. 3,367,778 issued Feb. 6, 1968; SchouwenaarsBritish Pat. No. 723,019 issued Feb. 2, 1955; lllingsworth et a1. FrenchPat. No. 1,520,821 issued Mar. 4, 1968; lllingsworth U.S. Pat. No.3,501,307 issued Mar. 17, 1970; lves U.S. Pat. No. 2,563,785 issued Aug.7, 1951; Knott et al. U.S. Pat. No. 2,456,953 issued Dec. 21, 1948; andLandU.S. Pat. No. 2,861,885 issued Nov. 25, 1958.

The emulsions used with this invention may be sensi-' McVeigh U.S. Pat.No. 3,297,447 issued Jan. 10, 1967;

and Dunn U.S. Pat. No. 3,297,446 issued Jan. 10, 1967.

The silver halide emulsions used with this invention may contain speedincreasing compounds such as polyalkylene glycols, cationic surfaceactive agents and thioethers or combinations of these as described inPiper U.S. Pat. No. 2,886,437 issued May 12, 1959; Dann et al. U.S. Pat.No. 3,046,134 issued July 24, 1962; Carroll et al. U.S. Pat. No.2,944,900 issued July 12, 1960; and Goffe U.S. Pat. No. 3,294,540 issuedDec. 27, 1966.

The silver halide emulsions used in the practice of this invention canbe protected against the production of fog and can be stabilized againstloss of sensitivity during keeping. Suitable antifoggants andstabilizers each used alone or in combination include thiazolium saltsdescribed in Brooker et al. U.S. Pat. No.

2,131,038 issued Sept. 27, 1938; and Allen et-al. U.S. Pat. No.2,694,716 issued Nov. 16, 1954; the azaindenes described in Piper U.S.Pat. No. 2,886,437 issued May 12, 1959; and Heimback et al. U.S. Pat.No. 2,444,605 issued July 6, 1948; the mercury salts as described inAllen et al. U.S. Pat. No. 2,728,663 issued Dec. 27, 1955; the urazolesdescribed in Anderson et a1. U.S. Pat. No. 3,287,135 issued Nov. 22,1966; the sulfocatechols described in Kennard et al. U.S. Pat. No.3,236,652 issued Feb. 22, 1966, the oximes described in Carroll et al.British Pat. No. 623,448 issued May 18, 1949; nitron; nitroindazoles;the mercaptotetrazoles described in Kendall et al. U.S. Pat. No.2,403,927 issued July 16, 1946; Kennard et a1 U.S. Pat. No. 3,266,897issued Aug. 16, 1966; and Luckey et al. U.S. Pat. No. 3,397,987 issuedAug. 20, 1968; the polyvalent metal salts described in Jones U.S. Pat.No. 2,839,405 issued June 17, 8; the thiuronium salt described in Herzet al. U.S. Pat. No. 3,220,839 issued Nov. 30, 1965; the palladium,platinum and gold salts described in Trivelli et al. U.S. Pat. No.2,566,263 issued Aug. 28, 1951; and Yutzy et a1 U.S. Pat. No. 2,597,915issued May 27, 1952.

The photographic and other hardenable layers used in the practice ofthis invention can be hardened by various organic or inorganichardeners, alone or in combination, such as the aldehydes, and blockedaldehydes as described in Allen et al. U.S. Pat. No. 3,232,764 issuedFeb. 1966, ketones, carboxylic and carbonic acid derivatives, fulfonateesters, sulfonyl halides and vinyl sulfonyl ethers as described inBurness et al. U.S. Pat. No. 3,539,644 issued Nov. 10, 1970, activehalogen compounds, epoxy compounds, aziridines, active olefins,isocyanates, carbodiimides, polymeric hardeners such as oxidizedpolysaccharides like dialdehyde starch and oxyguargum and the like.

The photographic emulsions and elements described in the practice ofthis invention can contain various colloids alone or in combination asvehicles, binding agents and various layers. Suitable hydrophilicmaterials include both naturally-occurring substances such as proteins,for example, gelatin, gelatin derivatives, cellulose derivatives,polysaccharides such as dextran, gum arabic and the like; and syntheticpolymeric substances such as water soluble polyvinyl compounds likepoly(- vinylpyrrolidone), acrylamide polymers and the like.

The described photographic emulsion layers and other layers of aphotographic element employed in the practice of this invention can alsocontain alone or in combination with hydrophilic, water permeablecolloids, other synthetic polymeric compounds such as dispersed vinylcompounds such as in latex form and particularly those which increasethe dimensional stability of the photographic materials. Suitablesynthetic polymers include those described for example, in Nottorf U.S.Pat. No. 3,142,568 issued July 28, 1964; White U.S. Pat. No. 3,193,386issued July 6, 1965; Houck et al. U.S. Pat. No. 3,062,674 issued Nov. 6,1962; Houck et al. U.S. Pat. No. 3,220,844 issued Nov. 30, 1965; Ream eta1. U.S. Pat. No. 3,287,289 issued Nov. 22, 1966; and Dykstra U.S. Pat.No. 3,411,911 issued Nov. 19, 1968. Particularly effective are thosewater-insoluble polymers of alkyl acrylates and methacrylates, acrylicacid, sulfoalkyl acrylates or methacrylates, those which havecross-linking sites which facilcurring sulfobetaine units as describedin Dykstra Canadian Pat. No. 774,054.

The photographic elements used with this invention may in addition tothe charge control agents described contain conducting layers, orcompounds which may comprise soluble salts, e.g., chlorides, nitrates,etc., evaporated metal layers, ionic polymers such as those described inMinsk U.S. Pat. No. 2,861,056 issued Nov. 18, 1958 and Sterman et al.U.S. Pat. No. 3,206,312 issued Sept. 14, 1965, or insoluble inorganicsalts such as those described in Trevoy U.S. Pat. No. 3,428,451 issuedFeb. 18, 1969.

The photographic layers and other layers of a photographic elementemployed and described herein can be coated on a wide variety ofsupports in addition to those mentioned specifically above. Theseinclude cellulose nitrate film, poly(viny1 acetal) film, polystyrenefilm, and related films or resinous materials, as well as glass, paper,metal and the like. Typically, a flexible support is employed,especially a paper support, which can be partially acetylated or coatedwith baryta and/or an alpha-olefin polymer, particularly a polymer of analpha-olefin containing 20 to carbon atoms such as polyethylene,polypropylene, ethylenebutene copolymers and the like.

As alluded to above, the radiation sensitive layers employed in thepractice of this invention may contain surfactants such as saponin;anionic compounds such as the alkyl aryl sulfonates described inBaldesiefen U.S. Pat. No. 2,600,831 issued June 17, 1952; amphotericcompounds such as those described in Ben-Ezra U.S. Pat. No. 3,133,816issued May 19, 1964; and water soluble adducts of glycidol and an alkylphenol I such as those described in Olin Mathieson British Pat.

No. 1,022,878 issued Mar. 16, 1966; and Knox U.S. Pat. No. 3,514,293issued May 26, 1970.

The photographic elements employed in the practice of this invention maycontain matting agents such as starch, titanium dioxide, zinc oxide,silica, polymeric beads including beads of the type described in Jelleyet al. U.S. Pat. No. 2,992,101 issued July 11, 1961 and Lynn U.S. Pat.No. 2,701,245 issued Feb. 1, 1955; and alkali soluble polymericparticles of the type described in Jelley et al. U.S. Pat. No.2,992,101. 9

The photographic layers used in the practice of this invention may becoated by various coating procedures including dip coating, air knifecoating, curtain coating, or extrusion coating using hoppers of the typedescribed in Beguin U.S. Pat. No. 2,681,294 issued June 15, 1954. Ifdesired, two or more layers may be coated simultaneously by theprocedures described in Russell U.S. Pat. No. 2,761,791 issued Sept. 4,1956; Hughes U.S. Pat. No. 3,508,947 issued Apr. 28, 1970; and WynnBritish Pat. No. 837,095 issued June 9, 1960..

This invention may be used with elements designed for colloid transferprocesses such as described in Yutzy et al. U.S. Pat. No. 2,716,059issued Aug. 23, 1953; silver salt diffusion transfer processes such asdescribed in Rott U.S. Pat. No. 2,352,014 issued June 20, 1944; LandU.S. Pat. No. 2,543,181 issued Feb. 27, 1951; Yackel et al. U.S. Pat.No. 3,020,155 issued Feb. 6, 1962; and Land U.S. Pat. No. 2,861,885issued Nov. 25, 1958; color image transfer processes such as describedin Rogers U.S. Pat. Nos. 3,087,817 issued Apr. 30, 1963; U.S. Pat. No.3,185,567 issued May 25, 1965; and U.S. Pat. No. 2,983,606 issued May 9,1961; Weyerts et al. U.S. Pat. No. 3,253,915 issued May 31,

1966; Whitmore et a1 U.S. Pat. No. 3,227,550, issued Jan. 4, 1966; Barret al. U.S. Pat. No. 3,227,551 issued Jan. 4, 1966; Whitmore et a1 U.S.Pat. No. 3,227,552 issued Jan. 4, 1966; and Land U.S. Pat. Nos.3,415,644 issued Dec. 10, 1968; U.S. Pat. No. 3,415,645 issued Dec. 10,1968; and U.S. Pat. No. 3,415,646 issued Dec. 10, 1968; and imbibitiontransfer processes as described in Minsk U.S.. Pat. No. 2,882,156 issuedApr. 14, 1959.

This invention may be used in elements designed for recording print outimages as described in Fallesen US. Pat. No. 2,369,449 issued Feb. 13,1945 or Bacon et a1. U.S. Pat. No. 3,447,927 issued June 3, 1969; directprint images as described in Hunt U.S. Pat. No. 3,033,682 issued May 8,1962 and McBride U.S. Pat. No. 3,287,137 issued Nov. 22, 1966; elementsdesigned for processing by heat as described in Sorensen et al. U.S.Pat. No. 3,152,904 issued Oct. 13, 1964; Morgan et al U.S. Pat. No.3,457,075 issued July 22, 1969; 'Stewart et a1 U.S. Pat. No. 3,312,550issued Apr. 4, 1967; Colt U.S. Pat. No. 3,418,122 issued Dec. 24, 1968;Yutzy et a1. U.S. Pat. No. 3,392,020 issued Feb. 8, 1965; Humphlett etal. U.S. Pat. No. 3,301,678 issued Jan. 31, 1967; and Haist et al. U.S.Pat. No. 3,531,285 issued'Sept. 29,1970.

This invention may be used with elements designed for color photography,for example, elements containing color-forming couplers such as thosedescribed in Frohlic et al. U.S. Pat. No. 2,376,679 issued May 22, 1945;Jelley et al. U.S. Pat. No. 2,322,027 issued June 15, 1943; Fierke etal. U.S. Pat. No. 2,801,171 issued July 30, 1957; Godowsky U.S. Pat. No.2,698,794 is sued Jan. 4, 1955; Barr et al. U.S. Pat. No. 3,227,554issued Jan. 4, 1966; Graham et al. U.S. Pat. No. 3,046,129 issued July24, 1962; Vittum et al. U.S. Pat. No. 2,360,290 issued Oct. 10, 1944;and Thirtle et al. U.S. Pat. No. 2,701,197 issued Feb. 1, 1955; orelements to be developed in solutions containing colorforming couplerssuch as those described in Mannes et al. U.S. Pat. No. 2,252,718 issuedAug. 19, 1941; Carroll et al. U.S. Pat. No. 2,592,243 issued Apr. 18,1952; and Schwan et al. U.S. Pat. No. 2,950,970 issued Aug. 30, 1966;and in false-sensitized color materials such as those described inHanson U.S. Pat. No. 2,763,549 issued Sept. 18, 1956.

Photographic elements prepared according to this invention can beprocessed by various methods including processing in alkaline solutionscontaining conventional developing agents such as hydroquinones,catechols, aminophenols, 3-pyrazolidones, phenylenediamines, ascorbicacid derivatives, hydroxylamines, hydrazines, reductones and the like;web processing such as described in Tregillus et al. U.S. Pat. No.3,179,517 issued Apr. 20, 1965; stabilization processing as described inRussell et al. Stabilization Processing of Films and Papers, PSAJournal, Vol. 16B, August, 1950; monobath processing as described inLevy Combined Development and Fixation of Photographic Images withMonobaths, Phot. Sci. and Eng., Vol. 2, No. 3, October, 1958, and Barneset al. U.S. Pat. No. 3,392,019 issued July 9, 1968. If desired, thephotographic elements of this invention can be processed in hardeningdevelopers such as those described in Allen et al. U.S. Pat. No.3,232,761 issued Feb. 1, 1966; and in roller transport processors suchas those described in Russell et al. U.S. Pat. No. 3,025,779 issued Mar.20, 1962; or by surface application process-

1. A MULTILAYER RADIATION SENSITIVE ELEMENT OF THE TYPE SUBJECT TOTRIBOELECTRIC CHARGING UPON IMPACT AND DISSOCIATION WITH ANOTHERUNSUALLY DISSIMILAR MATERIAL SAID ELEMENT HAVING A SURFACE THEREOFMODIFIED AGAINST GENERATION OF TRIBOELECTRICAL CHAROES SUFFICIENT INELECTRICAL POTENTIAL TO CAUSE STATIC DISCHARGES, SAID ELEMENT COMPRISINGA BASE AND AT LEAST ONE RADIATION SENSITIVE LAYER AND INCLUDING AT LEASTONE SURFACE THEREOF AT LEAST ONE CHARGE CONTROL AGENT IN AN AMOUNTSUFFICIENT TO LIMIT THE TRIBOELECTRIC CHARGING OF SAID SURFACE TO ANELECTRICAL CHARGE OF FROM ABOUT -10 TO ABOUT +10 ESU/CM2 AS DETERMINEDBY IMPACT ELECTRIFICATION OF 20 PSI IMPACT PRESSURE AT 5 PERCENTRELATIVE HUMIDITY AND 70*F. AGAINST A STAINLESS STEEL OR ANODIZEDALUMINUM IMPACTING SURFACE; SAID CHARGE CONTROL AGENT BEING SELECTEDFROM THE GROUP CONSISTING OF: A. SURFACTANT MATERIALS HAVING THE GENERICSTRUCTURE:
 2. R1 AND R2 ARE SELECTED FROM THE GROUP CONSISTING OFUNSATURATED HYDROCARBON, ARYL AND SUBSTITUTED ARYL RESIDUES;
 2. R1 andR2 are selected from the group consisting of unsaturated hydrocarbon,aryl and substituted aryl residues;
 2. The radiation sensitive elementof claim 1 wherein said radiation sensitive layer is a gelatino silverhalide emulsion.
 3. The radiation sensitive element of claim 2 whereinsaid charge control agent is selected from the group consisting of: A.those compounds of group (A) wherein A is selected from the groupconsisting of partially fluorinated hydrocarbon chains and fluorocarbonchains; B. sodium and potassium salts of substituted benzene sulfonicacids; C. non-polymeric compounds containing at least 2 carboxylic acidgroups; D. polymeric compounds having structural formulas selected fromthe group consisting of:
 3. R1 represents the atoms of a polymericstructure in which case R2 is selected from the group consisting of Hand as defined in (1) and (2) above; and M is selected from the groupconsisting of H, NH4 and alkali metal cations; and F. mixtures thereof.3. R1 REPRESENTS THE ATOMS OF A POLYMERIC STRUCTURE IN WHICH CASE RS ISSELECTED FROM THE GROUP CONSISTING OF H AND AS DEFINED IN (1) AND (2)ABOVE; AND M IS SELECTED FROM THE GROUP CONSISTING OF H, NH4 AND ALKALIMETAL CATIONS; AND F. MIXTURES THEREOF.
 4. The radiation sensitiveelement of claim 3 including a protective overcoat over said gelatinosilver halide emulsion and wherein said sufficient amount of said chargecontrol agent is at the surface of said protective overcoat.
 5. Theradiation sensitive element of claim 4 wherein said charge control agentis selected from the group consisting of: p-nitrosophenol, sodium salt;p-aminobenzoic acid; p-nitrobenzoic acid; 2,4,6-trinitrobenzoic acid;sodium benzoate; p-nitrophenol; picric acid; trinitroresorcinol;p-nitrobenzene sulfonic acid; 3-nitrophthalic acid; p-nitrocinnamicacid; dih benzene phosphonate; p-nitrobenzene sulfonic acid, sodiumsalt; p-nitrophenylacetonitrile; p-nitrophenylacetic acid;p-nitrophenoxy acetic acid; 3-nitrochalcone; 2,6-dinitrothymel;2,4-dinitro-1-naphthol-7-sulfonic acid; 4-nitrophthalic acid;p-nitrobenzamide; 2,4,6-trinitrobenzene sulfonic acid; m-nitrobenzenesulfonic acid, sodium salt; p-nitrobenzene sulfonic acid, dibutylaminesalt; 4-chloro-m-toluene sulfonic acid; p-fluorobenzene sulfonic acid;p-toluene sulfonic acid (hereinafter p-t.s.a.); p-chlorobenzene sulfonicacid, sodium salt; p-bromobenzene sulfonic acid, sodium salt;2,5-dichlorobenzene sulfonic acid; p-hydroxybenzene sulfonic acid,sodium salt; o-(carboxy methoxy) benzoic acid; p-hydroxy benzoic acid;p-chlorophenylacetic acid; 4,4''-biphenyl disulfonic acid;2,5-dichlorosulfanilic acid, sodium salt 4-sulfophthalic acid, monosodium salt; 2,2''-diphenic Acid; trimellitic acid; benzene sulfonicacid (hereinafter b.s.a.); b.s.a., didodecylamine salt; b.s.a.,dibutylamine salt; p-t.s.a., tridodecylamine salt; p-t.s.a.,didodecylamine salt; p-t.s.a., triethylamine salt; 4-sulfophthalic acid,dibutylamine salt; b.s.a., tridodecylamine salt; b.s.a. tributylaminesalt; p-t.s.a., triethylamine salt; p-t.s.a., tributylamine salt;pyromellitic acid; terephthalic acid; phthalic acid; mellitic acid;citric acid; salicyclic acid; d-tartaric acid; succinic acid; oxalicacid; malonic acid; malic acid; maleic acid; adipic acid; fumaric acid;hydroquinone; glutaric acid; l-tartaric acid; 50-50 d-, l-tartaric acid;pyromellitic acid, mono sodium salt;1,3-dicarboxymethyl-5-benzenesulfonic acid, sodium salt; pyromelliticacid nh4 ph 4.3; pyromellitic acid nh4 ph 8.2; 5-sulfoisophthalic acid,sodium salt; 5-sulfosalicyclic acid, trimellitic acid, trimesic acid,compounds of the following empirical formulas
 6. The radiation sensitiveelement of claim 4 including a backing layer and wherein said sufficientamount of said charge control agent is at the surface of said backinglayer.
 7. The radiation sensitive element of claim 4 wherein said basecomprises a film of a polymer selected from the group consisting ofcellulose ester, polyester and polycarbonate materials.
 8. The radiationsensitive element of claim 3 wherein said film is selected from thegroup consisting of cellulose acetate, cellulose acetate propionate andpoly(ethylene terephthalate).
 9. The radiation sensitive element ofclaim 8 wherein said charge control agent is selected fRom the groupconsisting of: the sodium and potassium salts of substituted benzenesulfonic acids, polyethylene pyromellitate, the compound having thefollowing empirical formula:
 10. A radiation sensitive element as inclaim 8, wherein said charge control agent isperfluorosulfonamido-(N-propyl-3-N,N,N-trimethyl)ammonium iodide.
 11. Amultilayer radiation sensitive element of the type subject totriboelectric charging upon impact and dissociation with anothermaterial, said element having a surface thereof modified againstgeneration of triboelectrical charges sufficient in electrical potentialto cause static discharges, said element comprising a base and at leastone radiation sensitive layer and including at at least one surface ofsaid element at least one charge control agent in an amount sufficientto limit the triboelectric charging of said surface to an electricalcharge of from about -10 to about +10 esu/cm2, as determined by impactelectrification of 20 psi impact pressure at 5 percent relative humidityand 70*F. against a stainless steel or anodized aluminum impactingsurface; said charge control agent being selected from compounds of thefollowing structural formula:
 12. The element according to claim 11wherein the charge control agent is present at said surface of theelement in the amount of from about 0.2 to about 4 micrograms/cm2 ofsurface.
 13. The radiation sensitive element of claim 11 wherein saidradiation sensitive layer is a gelatino silver halide emulsion.
 14. Theradiation sensitive element of claim 13 including a protective overcoatover said gelatino silver halide emulsion and wherein at least onecharge control agent is present in said overcoat in the amount of fromabout 0.3 to about 2.0g./g. of gelatin by dry weight of gelatin.
 15. Theradiation sensitive element of claim 14 including a backing layer andwherein at least one charge control agent is present also at the surfaceof said backing layer in the amount of from about 0.2 to about 4micrograms/cm2 of surface.
 16. The radiation sensitive element of claim13 wherein the base comprises a film of a polymer selected from thegroup consisting of cellulose ester, polyester and polycarbonatematerials.
 17. The radiation sensitive element of claim 14 wherein thebase comprises a film of a polymer selected from the group consisting ofcellulose acetate, cellulose acetate propionate, and poly(ethyleneterephthalate).
 18. The radiation sensitive element of claim 15 whereinthe base comprises a film of a polymer selected from the groupconsisting of cellulose acetate, cellulose acetate propionate, andpoly(ethylene terephthalate).
 19. The radiation sensitive element ofclaim 13 wherein the element is a photographic film element.
 20. Theradiation sensitive element of claim 13 wherein the element is an X-rayfilm element.
 21. The radiation sensitive element of claim 13 whereinthe element is an aero film element.
 22. The element according to claim13 wherein the charge control agent is selected from p-nitrosophenol,sodium salt; p-aminobenzoic acid; p-nitrobenzoic acid;2,4,6-trinitrobenzoic acid; sodium benzoate; p-nitrophenol; picric acid;trinitroresorcinol; p-nitrobenzene sulfonic acid; 3-nitrophthalic acid;p-nitro-cinnamic acid; dih benzene phosphonate; p-nitrobenzene sulfonicacid, sodium salt; p-nitrophenylacetonitrile; p-nitrophenylacetic acid;p-nitrophenoxy acetic acid; 3-nitrochalcone; 2,6-dinitrothymol;2,4-dinitro-1-naphthol-7-sulfonic acid; 4-nitrophthalic acid;p-nitrobenzamide; 2,4,6-trinitrobenzene sulfonic acid; m-nitrobenzenesulfonic acid, sodium salt; p-nitrobenzene sulfonic acid, dibutylaminesalt; 4-chloro-m-toluene sulfonic acid; p-fluorobenzene sulfonic acid;p-toluene sulfonic acid (hereinafter p-t.s.a.); p-chlorobenzene sulfonicacid, sodium salt; p-bromobenzene sulfonic acid, sodium salt;2,5-dichlorobenzene sulfonic acid; p-Hydroxybenzene sulfonic acid,sodium salt; o-(carboxy methoxy) benzoic acid; p-hydroxy benzoic acidp-chlorophenylacetic acid; 4,4''-biphenyl disulfonic acid;2,5-dichlorosulfanilic acid, sodium salt; 4-sulfophthalic acid, monosodium salt; 2,2''-diphenic acid; trimellitic acid; benzene sulfonicacid (hereinafter b.s.a.); b.s.a., didodecylamine salt; b.s.a.,dibutylamine salt; p-t.s.a., tridodecylamine salt; p-t.s.a.,didodecylamine salt; p-t.s.a., triethylamine salt; 4-sulfophthalic acid,dibutylamine salt; b.s.a., tridodecylamine salt; b.s.a., tributylaminesalt; p-t.s.a., triethylamine salt; p-t.s.a., tributylamine salt;pyromellitic acid; terephthalic acid; phthalic acid; mellitic acid;salicyclic acid; hydroquinone; pyromellitic acid, mono sodium salt;1,3-dicarboxymethyl-5 benzenesulfonic acid, sodium salt; pyromelliticacid nh4 , ph 4.3; pyromellitic acid NH4 , ph8.2; 5-sulfoisophthalicacid, sodium salt; 5-sulfosalicyclic acid; trimellitic acid; trimesicacid; and mixtures thereof.
 23. The element according to claim 22wherein said element is a photographic film element.
 24. The radiationsensitive element of claim 13 including a backing layer and wherein atleast one charge control agent is present at the surface of said backinglayer in the amount of from about 0.2 to about 4 micrograms/cm2 ofsurface.
 25. The element according to claim 22 including a backing layerand wherein at least one of said charge control agents is present at thesurface of said backing layer in the amount of from about 0.2 to about 4micrograms/cm2 of surface.
 26. The element according to claim 25 whereinthe charge control agent is a substituted benzene sulfonic acid or asodium or potassium salt of a substituted benzene sulfonic acid.
 27. Amultilayer radiation sensitive element of the type subject totriboelectric charging upon impact and dissociation with anothermaterial, said element having a surface thereof modified againstgeneration of triboelectrical charges sufficient in electrical potentialto cause static discharges, said element comprising a base and at leastone radiation sensitive layer and including at at least one surface ofsaid element at least one charge control agent in an amount sufficientto limit the triboelectric charging of said surface to an electricalcharge of from about -10 to about +10 esu/cm2 as determined by impactelectrification of 20 psi impact pressure at 5 percent relative humidityand 70*F. against a stainless steel or anodized aluminum impactingsurface; said charge control agent being selected from the groupconsisting of materials having the generic structure: (A-Z(CH2)n - D)+ Xwherein: A is a member selected from the group consisting of hydrocarbonchains, partially fluorinated hydrocarbon chains, and fluorocarbonchains; Z is a member selected from the group consisting of:
 28. Theelement of claim 27 wherein A in said structure is hydrocarbon chain,partially fluorinated hydrocarbon chain or fluorocarbon chain, and Z is29. The element of claim 28 wherein X is I.
 30. The element of claim 28including a protective overcoat over said radiation sensitive layer andwherein said charge control agent is present at the surface of saidovercoat.
 31. The element of claim 28 including a backing layer andwherein said charge control agent is present at the surface of saidbacking layer.
 32. The element of claim 30 including a backing layer andwherein said charge control agent is present also at the surface of saidbacking layer.
 33. The element of claim 28 including a backing layer andwherein there is present at the surface of said backing layer from about0.2 to about 4 micrograms/cm2 of surface of a charge control agentselected from substituted benzene sulfonic acids and sodium andpotassium salts of substituted benzene sulfonic acids.
 34. The elementof claim 27 wherein said base comprises paper.
 35. The radiationsensitive element of claim 28 wherein A in said structure is ahydrocarbon chain and D is lower alkyl.
 36. The radiation sensitiveelement of claim 35 wherein said charge control agent is
 37. Theradiation sensitive element of claim 28 wherein A in said structure is afluorocarbon chain, D is lower alkyl and Z is
 38. The radiationsensitive element of claim 28 wherein said charge control agent is 39.The element of claim 38 wherein the radiation sensitive layer is ahydrophilic, water permeable colloid containing silver halide emulsionlayer, said element includes a protective overcoat over said emulsionlayer and at least one of said charge control agents is present in saidovercoat in the amount of from about 0.3 to about 2.0g./g of hydrophilicwater permeable colloid by dry weight of colloid.
 40. The radiationsensitive element of claim 39 including a backing layer and wherein atleast one of said charge control agents is present also at the surfaceof said backing layer in the amount of from about 0.2 to about 4micrograms/cm2 of surface.
 41. A multilayer radiation sensitive elementof the type subject to triboelectric charging upon impact anddissociation with another material said element having a surface thereofmodified against generation of triboelectrical charges sufficient inelectrical potential to cause static discharges, said element comprisinga base and at least one radiation sensitive layer and including at atleast one surface of said element at least one charge control agent inan amount sufficient to limit the triboelectric charging of said surfaceto an electrical charge of from about -10 to about +10 esu/cm2 asdetermined by impact electrification of 20 psi impact pressure at 5percent relative humidity and 70*F. against a stainless steel oranodized aluminum impacting surface; said charge control agent beingselected from multifunctional carboxylic acids of the general formula:HOOC-R-COOH wherein R is selected from the group consisting of:
 42. Theelement according to claim 41 wherein the charge control agent ispresent at said surface of the element in the amount of from about 0.2to about 4 micrograms/cm2 of surface.
 43. The radiation sensitiveelement of claim 42 wherein said charge control agent is selected fromcitric acid; d-tartaric acid; 1-tartaric acid; succinic acid; oxalicacid; maloric acid; malic acid; maleic acid; adipic acid; fumaric acid;and glutaric acid.
 44. A multilayer radiation sensitive element of thetype subject to triboelectric charging upon impact and dissociation withanother material said element having a surface thereof modified againstgeneration of triboelectrical charges sufficient in electrical potentialto cause static discharges, said element comprising a base and at leastone radiation sensitive layer and including at at least one surface ofsaid element at least one charge control agent in an amount sufficientto limit the triboelectric charging of said surface to an electricalcharge of from about -10 to about +10 esu/cm2 as determined by impactelectrification of 20 psi impact pressure at 5 percent relative humidityand 70*F. against a stainless steel or anodized aluminum impactingsurface; said charge control agent being selected from polymericcompounds having structural formulas selected from the group consistingof:
 45. The element according to claim 44 wherein the charge controlagent is present at said surface of the element in the amount of fromabout 0.2 to about 4 micrograms/cm2 of surface.
 46. The radiationsensitive element of claim 44 wherein said charge control agent isselected from polyethylene pyromellitate; copolymer of dimethylformatewith Beta -propiolactone; and copolymer of dimethylformate withtrimellitic anhydride.
 47. A multilayer radiation sensitive element ofthe type subject to triboelectric charging upon impact and dissociationwith another material said element having a surface thereof modifiedagainst generation of triboelectrical charges sufficient in electricalpotential to cause static discharges, said element comprising a base andat least one radiation sensitive layer and including at at least onesurface of said element at least one charge control agent in an amountsufficient to limit the triboelectric charging of said surface to anelectrical charge of from about -10 to about +10 esu/cm2 as determinedby impact electrification of 20 psi impact pressure at 5 percentrelative humidity and 70*F. against a stainless steel or anodizedaluminum impacting suface; said charge control agent being selected fromlower alkyl phosphates.
 48. The element according to claim 44 whereinthe charge control agent is present at said surface of the element inthe amount of from about 0.2 to about 4 micrograms/cm2 of surface. 49.The radiation sensitive element according to claim 47 wherein saidcharge control agent is Ethyl Dihydrogen Phosphate, Butyl DihydrogenPhosphate, or Dibutyl Hydrogen Phosphate.